I ordered the Cowon C2 a few months ago and have been trying to make it work for me. Sound quality wise its great and I thought I could get past the horrific UI but I can't. I've tried some of the skins out there but its simply just not a very usable device. I probably could have gotten past that but I've had issue with its format support and the only way it supports playlists is via WMP which I have no intention of using.
So now I'm back to my Player 4.2 which while not a bad device isn't perfect. Its a pain to keep charged and SQ isn't bad but I've had issues where occasionally it hiccups. Is there a well compiled list on here of Android players that support USB DACs? I feel like that might be the best solution.