I've owned several Iriver players. In my opinion the H100 and H300 series sound best. I've heard all of them with my Sennheiser PMX 200, and MX 400 (the stock earphone). The H100, H300 and H10 with my AKG K-601
from excellent to average:
H100 or H300
As far as audio quality is concerned the H100 and H300 series ar equal, I haven't heard anything better so far.
I really like the DAC, however it's a bit unstable on low impedance headphones such as the stock ones, though sennheisser claims it to be 32 Ohm. It will run fine with my Sennheiser PMX 200 (30 Ohm). My AKG K601 is a bit too heavy at 120 Ohm though it still sounds heavenly. I'm looking for a good amp at them moment. (I can't imagine how it could sound even better than now
)
T10
Nice and very 'warm' sound (which I actually like, some people might not agree), however not as bright and clear as the H100/H300 (which sound pretty warm too).
I believe all players from the T serie sound equal (can anybody confirm this?) they are pretty cheap, probably even the best 'bang for the buck' players ever made.
U10
Not much difference to the T10, just a little weaker in the low tones. I completely dislike the firmware from the U10 serie, slow as hell, crashes from time to time, difficult to navigate from your pocket.
H10
Sounds like crap in the original firmware (compared to those above). The firmware itself is probably the best Iriver has ever created. Rocksolid, easy to use, easy to control. Such a shame it doesn't meet my first requirement: SOUND, not 'just sound', but that surprise everytime you turn it on. Under rockbox however it's acceptable: little shy on bass, but very good at the high tones.
At the moment I own a H120 and a 20GB H10. The H120 for it's audio quality, the H10 to just hack it to my needs (currently busy on implementing proper scroll support under Rockbox)
