[TwitchBladE]

I'm definitely going for the 271's next. And if I don't like it, amazon will pretty much return anything for a full refund as long as you return it within 30 days. 
 
Bass or coloration kind of doesn't matter to me, but if the headphones have some bass then I don't mind at all. If they have good enough mids for me to justify buying them, then I'll keep them. 

 

[TwitchBladE]

Well, it's been a while, but I've now listened to the k240, k271, and koss dj100 each for about two to three weeks. The first thing I'll say is that none of these really impressed me at all.
 
K240: The one I disliked the most. Cheap sounding bass that is flabby and weak. The mids are absolutely nothing special either- they basically fall between recessed and balanced, and sound peaky and unpleasant in the upper midrange. The highs are actually a bit too harsh for me on these also.
 
K271: These are easily the best of the three, but still not really what I was looking for. The k271 sounds MUCH more clear and clean when compared to the k240. When I amped them through my fiio e9, the bass was actually really nice. For the most part it was just sub bass, but it was deep, thick, and tight. The mids, while more clear than the k240, are still really sharp and peaky for some reason. They're not sibilant in the midrange, but they do have a strange edgy quality to them, which makes it annoying after a while. The highs are the best of the three however. Very clear and not too extended. The soundstage isn't as good as the k240, but neither of them are particularly good at soundstage anyway. Another thing to add, this headphone is easily the most detailed out of the three by far. 
 
Dj100: All around better than the k240 in every area except soundstage. The bass is decent, the mids are smooth but boring and can get pushed back by the bass at times. The highs almost perfectly fit what I was looking for though. They're very non fatiguing, but a little more is probably needed because the mids sound muffled at times. My major problem with these is that they sound boring. With these I forget that the music is even playing after a while.
 
I think I'm more disappointed though because after trying all of these headphones that people tend to recommend for midrange, out of all of these, my little koss ksc75 by far have the most forward and enjoyable mids I've heard on any headphone I've owned. It absolutely boggles my mind that if you spend 100 dollars you can't get a headphone that has a good enough midrange to justify buying anything above the ksc75...
 
I have a friend who owns a pair of Senn hd598's, and after listening to them, I was absolutely blown away by their midrange. I find it really strange that in order to get an upgrade that large from $12 headphones, you need to literally spend $200.  
 
 
 
 

 

[electropop]

Sorry to hear you haven't found anything good yet. 
 
But your mention of ksc75's really gives us more perspective. I thought they just eat crap compared to the K272 I have: minute pitch variations not apparent, very monotonic and while maybe engaging, not very good at extracting musical information. I get a kick out of different things, it simply must be. 
 
The KNS8400 might be something you'd like. I thought they trumped the K272s (objectively they do, but again, people have different flavors). But I am having a bit of trouble with the treble "boost", though I have gotten a bit used to it or burn-in has helped. I'd like to believe the latter... But the mid-range is easily the best in its class, when picking out musical cues or tabbing notes is crucial! I don't mean to say that they're analytic, though they are in many ways. I don't know, maybe I like to be able to hear everything instead of settling for optimal tonal balance and desired sound. 
 
I'm getting my Fischer Audio FA-003's soon and will try them against my 8400's. The K271/2 is an old design after all, about time something trumped them. Still an excellent headphone and I prefer them to the new Shure line (minus the 940, which I haven't heard) by a large margin, or the HD25-1's. 
 
The Sennheiser line-up with 555's and 595/8's do have a seductive presentation and they're quite easy to listen to. Where they failed me was that they were just a tad boring and not accurate enough. But if the mid-range was to your liking, I think the 555/8 is better value for your money and very similar to the 595/8. 

 

[overbybr]

This reply is not really helpful to the OP, but it might be helpful for future readers who are toying with buying the AKG K271 MKII 'phones. I was just reading this thread, and after having just bought a pair of the K271 MKII's, I was feeling a little underwhelmed with their performance on the low end (I feel that the upper register & the mid-range are very well done). That being said, don't underestimate your eq settings!
 
I found that I loved everything about the MKII's except the low end. I love the comfort, the looks, the features (dettachable mini-xlr, sound-mute switch, auto-adjust headband), & the balance they have between the highs & the mids. There are several posts here at Head-Fi that talk about the MKII's having a fairly neutral sound, and I agree with them. Being a bass player though, I like being able to pick out the bass riffs in songs or to occasionally be driven over my dance threshold (see Christian Finnegan) by a tight sounding low end beat.
 
I've been listening to my MKII's using my phone (HTC Incredible) & the doubletwist app, and powering the headphones through an iBasso T3. I found that by utilizing the equilizer on the doubletwist app, I could get the low end sound I was looking for. A perfect example of this is listening to Bulls on Parade by Rage Against the Machine. The tone that the bassist is using is absolutely rediculous sounding, and I found that by tweaking my eq, I could get a sound that made me smile. Afterall, I think its fair to say that the enjoyment we get from music is the reason we spend the time & money we do to get the setups we have.
 
As I said, its not really helpful for the OP, but if you're reading this post & are on the fence about the MKII's because you are concerned about their low end, do what others in this thread have recommended: Buy them, listen to them, play with your eq settings, & decide. You can usually return them to most places if you don't like them. Having played with my settings, these cans aren't going anywhere but on my head!
 
By the way, an equilzer is not meant to dial up the volume of a particular frequency band so you can hear more bass or treble. Its reason for existence is to compensate for audio inadequacies in a particular set of equipment or in a space. Check these two good reads on frequency response & equilizers.
[size=medium]http://www.ecoustics.com/electronics/products/articles/131062.html[/size]
[size=12pt]http://www.musicplayer.com/mpLandingContentPage.aspx?content_id=30829[/size]

 

[electropop]

Maybe it's just "too" tight
 
I found they are excellent for tabbing bass notes. Actually much better than many headphones that do have relatively more or down right exaggerated bass..

 

[zazex]

I had the AKH 271 II for about 6 months before selling them.
 
Very comfortable and well made
too light in the bass 
good midrange and upper midrange
decent treble, but too rolled off at the very top: lacked sparkle
 
 
 
 
 

 

[rus1234]

What did you get instead? What is your source setup and prefer genre? I was really leaning toward getting them.
 
 
This is my info I'd posted:
 
I need advice on buying my first real set of headphones.
-they will be used unamped at a PC for music/movies/games. My mp3s are high bit rate or FLACs.
-I like 80s rock & folk mainly, some trance & classical
-doesn’t matter whether open or closed cans. (isolation from ambient noise would be nice, but soundstage and imaging are more important)
-price range is $50-150max. looking for best value.
-I am 45 y/o and try to keep the volume a few clicks below optimal to avoid fatigue / conserve my hearing.
-I want something that's accurate, but unlocks hidden details. I want to fall in love with my collection again.

 

[TwitchBladE]

I didn't get anything instead, I'm still looking. I am currently trying to get a used k501 from somebody off of the for sale forums though. 
 
My setup: asus xonar d1 ---> foobar/asio/flac files, etc ---> fiio e9 ---> headphone.

 

[bookaboo]

Give the dt250 - 80 a go. I was looking for something exactly like what you described in your first post - a basically neutral can with smooth non fatiguing highs and a full but not overpowering bass and feel I have found it in the dt250.I liked them so much I have them in both the 250 and 80 ohm versions. The 80 ohms works better off the iPod and has a little more fuller mid bass and upper midrange which works well for rock and pop. The 250 ohm is more of a jazz, classical and acoustic can with a more spacious sound. I have been curious about the k271 also and went to audition one the other day - I came home loving my dt250s even more!