well I got the sony x and it has been great but I seen hifiman have released a new player
so the real question is, is it worth the upgrade from my Sony x?
also will the hifiman be able to play Flac?
I haven't heard the hm-602, but i do own both the hm-801 and sony x1050 and i would say that the sound quality seems so much better (still burning in the game amp for my iems) than the sony, but it loses on lot's of other things. Like hitmanx said, the hm-602 is thicker and thus less portable. It doesn't have a playlist feature (besides a cue list that only works on a single flac file) and it can't play video's or pictures and no wifi.
The only thing that you can gain from this is a better soundquality in exchange for lot's of features lost compared to the sony, but i still like my hm-801 though.