Whew, this one took longer than expected to get around to but it is finally done! Thanks to Fiio for including me on the X5ii tour! (I will have pictures up later tonight)
 
 
I'm going to skip all details of this DAP with exception of build quality, UI, and SQ. Even though most of this has been covered ad nauseum, those three parts are subjective.
 
 
Build Quality
The build quality of the X5ii is superb. The player feels solid in the hand, but not overly weighty as the first gen did. I personally enjoy the button layout, and all had a very good feel to them, with little to no squishiness. While the scroll wheel on the demo wheel has been said to need some work, I didn't find it too much different from the production X3ii. The display is BEAUTIFUL. I didn't think I would want a big display for a DAP until I tried it. Wow.
 
UI
The UI is snappy and for the most part intuitive. If you've browsed on any trackwheel based Fiio, you know what to expect. One thing I would like to see would be more minimal theme options, or at least more polished ones. This is obviously a minor nitpick and doesn't affect the usability of this player.
 
SQ
For reference, I didn't care for the first gen X5 (albeit I had different headphones at the time) or the X3ii. They were by no means bad, just not quite there for me. I will take a player with slightly less resolution if it has a tone I like. The DIYmods come to mind: they sound dated, but have a certain sweetness that I always found appealing.
 
The X5ii is without a doubt one of the most enjoyable DAPs I have experienced. The soundstage when using my UERMs was astounding, and combined with the ALO RX IEM amp was nothing short of stellar. The detail is there, but not so much that you lose the overall flow of the music. I still can't get over the soundstage. A particular album to reference is “Benji” by Sun Kil Moon. The player is very close to a true “natural” sound to me. If I had to find something truly wrong, it would be that it is almost too natural. Even though this is against my goals of a neutral sound, sometimes I like a little more coloration. While the EQ is an improvement from the last generation of Fiio players, I still feel like the EQ changes the feel of the player rather than simply sculpting it.
 
 
Conclusion
This is probably the best DAP for your money. It is a jack of all trades, and master of many. The sound signature will work well with several different headphones and IEMs. The USB DAC implementation was flawless across Windows AND Linux. If you can live with the form factor, I would say that you could buy this and leave Head-fi. Leave this forum of constant upgrades, and enjoy the quality that Fiio has produced in the X5ii.

 
Well, this one has taken a while for me. First of all, thank you Jack for letting my participate in the promotion, it was the only was I was able to afford this! :rolleyes:
 
So, a little background info here. I've gone through quite a few DAPs once I decided to try to make a main portable rig. I started from a modest Clip+, which as we all know is the gateway drug. It made me want an E6, then an E7, then a CMOYbb, and finally a C421. My DAP went to an Ipod, and finally a DIYmod. I thought the DIYmod/amp combo was my end game. It sounded great, had a TON of storage, and had that sexy “Head-fi stack” appeal. But something still didn't feel right. It was a bulky combo, and one I felt was quite fragile if I happened to drop it. The battery life on the C421 is superb, but the DIYmod isn't, especially for a music skipper like myself. And also I couldn't get over the fact that it just seemed like too warm of a rig for my already warm (at the time) IEMs and cans. I was so proud of it, and it truly was a conversation piece. But when I saw this deal, I couldn't resist, and sold it away to fund this. And you know what? I'm actually pretty damn happy now.
 
I've actually had this unit for a bit, and have used it with several IEMs of both types, and am currently using them with some KSC75's. Once December gets here I'll be testing this with my Tzar 350's and report back then as well. Maybe if I get some other full sized cans, I'll post that too. More information is better. Now to stop rambling!
 
 
 
PROS:

1. Stupid good battery life
2. Can be used as a separate amp, and actually does a pretty good job at it
3. The most durable DAP I've held yet.
4. Sounds great, with a slightly bright presentation that gives good detail.
5. The sound works PERFECTLY with warmer signatures. SM3, most of the higher dynamic IEMs (save for EX series) will even out with this player, and will sing.

 
 
EH:

1. The file naming issue isn't a huge deal, once you get a tagging program set.
2. No support for 24/96 FLAC
3. Very slight detail errors on the casing (I'm very neurotic about these things, so grain of salt on this one)
4. Because of the brighter signature, I feel there is a very slight bass rolloff. This player might make some IEMs too energetic.

 
CONS:

1. The firmware. While it isn't horrible for very simple tasks, it keeps this player from being a no question asked superpower. Jack has said there will be an update though, so fingers crossed. It's not enough to keep me from recommending it though.
2. Boot time. This is related to the firmware, and it reindexes everything, every time you boot. With proper tagging (thanks lee!) it boots in a minute or so if nothing has changed, but with several files/folders, prepare for a wait if you have added anything.

 
 
Alright, now on to the details.
 
PACKAGING:
 
The packaging was nice, a faux shiny leather case with a charger, USB cable, and some updated PAA-1 earbuds were included (PAA-1 is still one of my favorite earbuds, so that's a plus). I actually like the casing and stuff, although it would be nicer to see packaging that matched the handsome champagne color of the player. Not much else to say here, it did its job.
 
 
BUILD QUALITY:
 
Now THIS is a tough player. It is completely metal, with an acrylic plate on the back, and metal under that. I'm not gonna lie, I've dropped it a few times. The ONLY damage I see is some slight cracking in the acrylic backing. While this saddened me to no end (I love my things being in pristine condition), it affected the playing in NO WAY. Thanks again flash memory Speaking of dropping it, the other posters are completely accurate. You could kill someone with this thing, given enough force. It is a metal bar. I'm one of those people who feel I got a better product if it's heavier (see: stupid misconceptions of hifi).
 
It feels good in the hand. It's also a lot smaller than I imagined. When I saw the Studio, I thought “Wow, that thing is FAT”. But it really isn't so bad. I would say maybe 2 7^th gen Ipods on top of one another. It's really quite pocketable, and this is probably one of my favorite things about it. It isn't a pain to get out of my pants pocket, and doesn't look like I'm smuggling a bomb when it IS in my pocket. It works out quite nicely.
 
Aesthetically speaking, it's a gorgeous piece to me. While some prefer a different look, I've fallen for this finish. Around the jacks there are some markings where whatever cutting device made them didn't make it perfect. It is barely noticeable until you start nitpicking. Nitpicking like the flattened off edges, one of them on mine is slightly uneven. Would you think about this on a day to day basis? Not unless you have a lot of free time, and forgot your headphones at home (*cough cough*).
 
Despite these minor minor cosmetic flaws, I couldn't be happier with the build of this thing. Major respect to Jack and crew on that.
 
 
INTERFACE:
 
The Achilles heel of this player, and honestly the only negative thing I can say about it. I feel the UI isn't unusable, but very clunky and primitive. One BIG example is the index check every time you boot. This is an annoyance, and a very big one depending on if you've tagged your stuff properly. It could take quite a while if you have a ton of stuff on there.
 
That brings me to another thing, this thing is P-I-C-K-Y with tagging. Thankfully enough lee730 has a VERY good tutorial on how to batch tag all your stuff when your transfer it over. If I could change one thing and one thing only about this player, I would actually choose the tagging issues. For instance, accepting ID3v2 or letting things be tagged 1,2,3 instead of 01,02,03. I can live without an EQ. But I can't live with my tracks being unorganized, especially if it's an album I haven't heard before. But once you have your stuff started and playing, it works A-OK. I would like Last.fm scrobbling on here, but I can't really think of a Chinese DAP that supports that without Rockbox. Oh well :S
 
PERFORMANCE:
 
Back to the good! This thing sounds great. It may have been because my main IEM when I had my DIYmod was too warm for it (SM3), but it opened up on this player. I also had a few dynamics that I tested on this and I really do feel that this player evens out warmer/bassy IEMs in a good way. It seems to open up the 1K-7K area, and personally I felt more detail extraction. This is a double edged sword though. With IEMs such as the HF5, I felt that it was a little too bright. I didn't get to try my impedance adapter at the time I had them, but I felt that might have helped a bit. I'm a closet basshead though, so I want my bass very VERY punchy

The amp only part functions great. It gets very very loud (and makes me wonder if the DAP itself keeps the amp from being as powerful as it could be). It has a very clear, transparent sound with what I feel is a slight slight rolloff under 60hZ.
 
 
 
 
Overall, I love this mini brick. Would I buy it for MSRP? If the firmware gets updated, in a heartbeat. Would I otherwise? I would be more hesitant, but would definitely be content either way.