Ok, got mine just now in the mail (less than 20 minutes ago). And here's the quickest turn around time on a review for a product you've ever seen.

1st I want to say definitely opt for the line level cord. It not only sounds significantly better it also plays significantly louder. If I had to venture a guess I would say 10dB more than the standard output of the headphone out.
for this listening I used my Beyerdynamics DT880s flat cans with teflon silver cabling. On Cat Powers cover 'Dark end of the Street" the E5 produces a sound that is just so much more effortless and smooth. The iPhone 4's standard headphone jack isn't bad actually, but the E5 is several notches better in stereo effect, separation, bass response and transients. Dark end of the Street track had a much better clarity to the electric guitars picking and Cat Powers voice was less manish sounding and more seductive and melancholy.
Next track was Band of Horses 'On my way back home" This track can sound really awful on some setups and fantastic on others. This was pretty much the case here. iPhone sounded very boring and not very convincing. The E5 was much more crystalline and nice on the top end vs the very digital sound of the standard iPhone output. E5 was very much passable as a "high end" performer and I mean that. No it's not the end all be all like I've heard from portable amps costing several orders of magnitude more, but for a shitty Chinese <$30 device the E5 punches WAY above its weight class.
And now the battery I didn't charge is dead... So this is the end.
More to come maybes. So stay tuned... or not!!!!!
