Pros: Storage, a palette of EQ settings, ease of navigation
Cons: I should have bought this first!
After trying player after player to include the 602 I have come to realize this was the perfect match for me.
I too use the UM3X, but also Grado 325i's, K702's (300ohm) and Senn IE6's. This player just wants to push them all. Aside from the 35 presets The EQ settings are ENDLESS! (there are 4 available to dress to your hearts content)
I didn't need to find phones with the right "synergy" to make it sound great! Heck IMO if you pay $300+ for a DAP it should match at least something in your arsenal .....
Bottom line, I love it, great sound, great vids (I just found out but probably will never use), easy to navigate. Once again let me say the COWON J3 is a great, great player.