Pros: Great sound, EQ features and options, portable, battery
Cons: reliability, not the best UI
Well, i won't make a long review.
Having the iPod Nano V6, SansaClip+, SansaClip Fuse, iAudio 6 and a mix of older Sony's, iPod's etc ... I think the best sounding player to me was the iAudio 6. Followed by the iAudio J3. The difference is marginally, but somehow the 6 just performed a tiny bit better to my taste. The BBE+ etc effects just had a smoother and warming impact, where on the J3 it starts to sound a tad more cool, in some cases even mechanical (hissing etc), where the 6 kept composed.
But ... sadly, i only managed to enjoy the J3 for a few months when it died. The screen showed weird colors, like there was some graphic card issue and froze, it didn't respond to any button actions. Resetting, rebooting ... nothing. So i returned it, got a new one, after a few months ... the same happened.
So i've given up on this model. Might try some other iAudio devicse, but i have no confidence anymore in the J3.