@ delancyst: I think this is way to subjective to make a good answer. I think it is loud enough but I am still hoping for a comparison with an non EU one.
I did a Test now: Cowon J3 vs ZX1 same song same earbuts (as the only one I have two from they are the ones that came with the Iphone 4s) each player one ear. It is not easy to be precice, but the covon is about the same volume as the ZX1 when reduced to 35 from 40. I switched the ears and tested over and over again and sometimes I thought maybe more 34 sometimes 36. So I go with the 35. For those who do not have the J3 or tze ZX1: The Covon counts volume in 1-40 steps (when NOT EU-Volume caped) The ZX1 has a sidebar without numbers.
Anybody any thoughts on this?