Many are very impressed with the Sandisk Clip+ and Clip Zip when running Rockbox. Rockbox is not available for the Clip Sport. The Clip Sport keeps card memory contents in a separate database from internal memory. Each dabase is limited to 2,000 songs. There is an experimental firmware that allows 4,000 songs for each.This player seems to be positioned to compete against the ipod Shuffle. Compared to the Shuffle it is much more capable, however it is inferior to the Clip+ and Clip Zip functionality, except for battery life. The sound quality of these three though is around the same.
 
The Fiio M3 is close in price, but has much higher power output and better sound quality, although the sound quality of the Clip Sport is good. The M3 lacks FM radio though, and lacks a clip. The M3 has poor quality buttons that are not at all ergonomic. The M3 also keeps internal memory in a separate database from card memory. I have a 32GB Sandisk class 10 card in my Fiio M3, and don't use its internal memory. My Sandisk Clip Sport has a 16GB class 4 card in it, and I also use its internal memory. The M3 database allows up to 4,000 songs.
 
 
Read my Fiio M3 review. http://www.head-fi.org/products/fiio-m3-digital-portable-music-player/reviews/14785
 
Which do I like better, the Clip Sport or the Fiio M3? Each has its pluses and minuses. It is a hard decision. I want a player with the best of both of them. 8)  The buttons on the Clip Sport are very ergonomic and so much better than the M3 buttons. The FM radio and built in clip of the Clip Sport are nice.The better sound quality and higher power output of the M3 is nice. Both get around 24 hours of battery life playing mp3 files.

I have been waiting a few months for this player. Now that I have it, I am disappointed. Not due to the sound quality or the power output, which are both great, but due to the way the buttons are organized, and how poorly they feel. I also have a Rockboxed Clip Zip, Rockboxed Clip+, the Clip Sport, and a Fiio X1. The Clip Zip, Clip+, and Clip Sport have buttons that are ergonomicly spaced, and have a great feel. Unlike the X1, the M3 does not come with a skin. It also doesn't have a built in clip like the Clip+, Clip Zip, and Clip Sport have. I hate the headphone jack on the bottom of the M3. I wanted it at the top or near the top. Hopefully it won't be on the bottom of any other Fiio players. I was hoping the case would be made of metal like on the X1, however it is plastic. There are some lightweight players made with a metal case. The Clip Zip, Clip+, and Clip Sport have FM radio, which the M3 lacks. The M3 also lacks dedicated volume buttons(which the Clip players have), with the up and down buttons on the M3 used for browsing also used to raise or lower the volume. So on M3 if one is browsing or changing settings, they need to return to the now playing screen to adjust the volume. Another annoyance is that the player can't be turned off without first turning on the screen. 
 
The firmware on the M3 is very primitive, although it is likely to improve over time. I doubt it will ever offer all the features that a Rockboxed Clip+ or Clip Zip offers(The M3 does give much more power output than these, and also has better sound quality). When using the M3 or the X1, I miss being able to easily make playlists on the player, especially being able to add an album at a time to a playlist. I also miss the adjustable crossfeed settings that Rockbox offers. The M3  offers longer battery life than the X1 or Rockboxed Clip+ or Clip Zip, but might be close to what the Clip Sport offers(The Clip Sport though is very limited in how many songs its databases can hold).  I haven't tested the M3 battery life. The instructions with the M3 say 16+ hours of battery life, however Fiio's website says 24+ hours. The M3 and X1 are also lacking variable speed playback with pitch correction, which Rockbox offers. Variable speed playback with pitch correction is important for those who listen to podcasts or lectures where the speaker is speaking slowly, and who want to listen to it at perhaps around 1.5x normal speed, and have it sound natural, and not like a chipmunk. I use 320 kbps mp3 files on my M3.
It occasionally starts skipping while playing, which others have described. At least this should hopefully be easy enough to fix with a firmware update. I am using the player with a class 10  32GB card.
 
 
Do I recommend that people buy the M3? Yes, since it probably has the best combination of sound quality, power output, and battery life in a light weight compact player. Could the M3 have been so much better? Yes, by having buttons like the Sandisk Clip Zip,  and Clip Sport have(or like those on the Clip+ although those those would have left less room for the display), and a built in clip as they have(although I would prefer if the clip is removable). Am I happy I bought the M3? Yes, as the Fiio M5 which is likely to have the sound quality of the M3, plus FM radio, bluetooth, and probably much longer battery life than the M3(when the bluetooth is disabled) probably won't be released until around a year from now.  Hopefully the M5 will also have a metal case, a clip that is removable, better buttons that are ergonomically shaped and placed, and many of the features that Rockbox offers. The M5 might not be out until the end of 2016 or  later though, and it might be much more expensive than the M3(hopefully $99 or less though)  so buying the M3 now seems to make sense even if you really want a player more like the what the M5 might be.

This is great for the price. Its sound reminds me of Stax headphones or electrostatic speakers, both of which I don't own, but have heard on a few occasions.  It needs extensive(100+ hours?) breaking in to help tame the highs and bring out the bass. If you want a slightly warmer sound or are treble sensitive, then choose the Panasonic RP-HJE355 instead, although some may want to buy both.

I bought this and the JVC HA-FX40 at around the same price($20 each). I like this for the better behaved highs, overall slight warmth, and what seems like a slightly better build quality. I like the HA-FX40 for its slightly better detail, although its highs are a bit too strong at times. The HJE355 has a very ergonomic shape and I think most people will find that it is very comfortable and fits well.
 
Since the  Panasonic RP-HJE355 and the JVC HA-FX40 are only around $20 each, I suggest people buy both!

The sound reminds me of the PX100. It is warm and detailed, with plenty of bass. It has more bass impact but less detail than the HJE355. The HJE355 also has better detail, better highs, and seems to isolate better. I bought the HJE450 before I bought the HJE355. Even though the HJE450 is good, I prefer the less expensive HJE355.

When I first started listening to this, it reminded me of the Sennheiser PX100. While the PX100 is open and this is closed, the warm detailed sound and  tight bass seemed similar(but of course more bass on the HAS650 since it is closed). I don't have the PX200II(a closed version of  the PX100) to compare it to. The sound on the HAS650 also reminded me of the HAS600, so I compared the two. The bass seems tighter on the HAS650 and there is also more detail. I guess since this is  cheaper than the PX200II, and it is also more efficient, some people might want to compare these directly. That would be an interesting contest.
 
This is so much more compact than the HAS600. It is only slightly larger than the HAS160. For the price, the HAS160 still seems like a better value. I was hoping this would be like the HAS160 but more refined. Instead it is a warmer headphone. This is around $20 less than the PX100II, and I prefer the sound on this to the PX100(I have the original PX100, not the PX100II, although they are said to be similar  enough).

I have both the HAFXC80 and HAFXC51. The FXC51 seems easier to insert due to its shape, while the FXC80 seems to have a bit more detail and be a bit more dynamic. I bought the FXC51 first, and didn't realize when I bought it that the FXC80 was only $13 more. I bought the FXC51 based on recommendations here.  
 
These IEMs use a micro driver which penetrates much further into the ear canal than the driver of a typical IEM. This makes the highs much better, as there is less reflection of the sound. It also leads to comfort issues, as the very hard driver enclosure is going deep into the ear. It also seems like different replacement tips won't be so easy to find. with practice, one develops a method for inserting these.
 
At first I hated the FXC51 due to comfort and fit issues, and without proper insertion there is very little bass. After a while I learned to like it enough(plenty of burn in also helped) that I wanted to buy the FXC80.
 
These are excellent for classical music, especially for violin and piano. The sound reminds me of open Sennheiser circumaural headphones, even though they have good isolation.
 
PS. After plenty of additional burn in, the bass is emerging nicely. I should have let these play for a week straight before listening to them.

This is a great value for the price. Of course I do prefer the highs and midrange detail  on the Sony E-888 and the E-888 is much more efficient, however the E888 seems to be at least $75 now if you can find it.The E-888 has a biocellulose diaphragm which helps make the sound be more detailed, and more dynamic.

This headphone was my first high quality one. It sounds extremely neutral with good bass that is in proportion to the other frequenciencies. The midrange and treble also sound natural. What this headphone lacks and what you get by stepping up to the Sony V900HD(aka 7509HD) is a higher level of midrange detail. For the price though, this is an excellent value, however this is not on the level of the 7509HD or CD1000.

 Not bad for under $20. The fit is great. This is a good IEM to sleep in, as it doesn't stick out from my ears(I assume that will probably be the case for many people). Isolation is also decent considering the comfort level.  It seems like the bass and treble are boosted and the midrange seems  recessed. Vocals seem dominated by the bass and treble. I boosted the midrange quite a bit and brought down the bass and treble somewhat with the equilizer on my mp3 player, and now it sounds much more natural. I usually don't use the equilizer on my mp3 players, however this IEM seems to need it. Overall I am pleased, however I would have preferred if it was better balanced, and not needing the use of the equilizer.
 
 

After being so pleasantly surprised by the $9 HA-S160, I was so curious to hear if this is better. Is it better? It has better bass than the HA-S160, but worse treble.  The midrange(including vocals) also sounds slightly recessed on this when compared to the HAS160. The bass sounds slightly exaggerated though, and not natural like it sounds on the HAS160. Overall I like the HAS160 better since it is better balanced.
 
 
PS. After a few more weeks of burn in the treble and detail have improved a bit more, while the bass has decreased. The bass is still slightly above normal, but not in as much excess as it was. The headphone is starting to sound much more neutral, which is what I prefer(though others may not).  I gave this so much burn in and it still seems to need more. Don't be discouraged if it doesn't sound so good right out of the package. Even after just 8 hours of burn in you will notice a big difference. Use slightly higher than normal listening volume for the burn in,  but don't overdo it. Those who don't like the HAS600 probably didn't give it enough burn in.
 
I also bought the JVC HAS650 which has 36mm drivers vs  40mm for the HAS600, however the driver quality in the HAS650 is better, and it has more detail and is more efficient. The HAS650 is much more compact. If the price of these is close, then get the HAS650. The HAS650 was also too bassy out of the package, however the bass is decreasing with burn in. Perhaps after extensive burn in I  the bass will moderate, and the detail and treble will improve even more, as was the case with the HAS600.

After being so satisfied with the HAS160 I wanted to see if this would be a good improvement on it. It isn't. While the bass is a bit better than on the HAS160, the treble is much worse. The HAS650 has better bass and better sound overall, and much better build quality. The treble on the HAS160 is  better than the treble on the HAS650 though. I am glad I bought the HAS160, HAS600, and the HAS650, and regret buying the HAS360. Save your money and don't buy this one. Ironically I paid less for the HAS600 than for the HAS360. Even though I regret buying this, I still think it sounds a bit better than the Portapro, and has a similar warm sound signature. Buy the HAS650 if you want a warm sound with extra bass. Buy the HAS160 if you want better treble and want a more balanced sound. Avoid this.

On another forum someone recommended this headphone. Since it was so cheap I thought I would try it. I was so impressed by its neutrality. It reminds me of the Sony V6. It has decent bass, however the bass is in proportion and sounds natural. The midrange and highs also sound natural. Of course it doesn't have all the detail of V6. Imo it is much better sounding than the Portapro and sounds almost as good as the PX100. The bass is better on the PX100, however the HAS160 has better highs.  Those who prefer a  warm sound signature like on the  PX100  would prefer the $34 JVC HA-S650 to this. They may even prefer the HAS650 to the PX100 as I do.
 
 This is a closed supraaural headphone, however the isolation isn't great. It is amazing how well this headphone compares to the PX100 and Portapro, which are around four times the price.