i am kind of audiophile, but about what am i talking, i think every body here is.
Actually i am using my iPhone 4 with a Shure SE315 (i didn't found it in your ranking...). My files are most in 256kbit/s AAC compression.
Is it worth to upgrade to a Sennheiser IE8 or even to a Ultimate Ears Custom in ear? I mean is the sound quality and the audio chip of the iPhone 4 good enough to hear a difference?
Btw someting different: Why is there no Number 1 in your ranking? And why are the customs not in the top 20?