Have Sony improved on their PC-side software since SonicStage and the initial versions of SonyConnect? The software that I used a couple of years ago was so terrible -- even compared to how bad most other software for interfacing with portable devices is -- that it was a complete deal-breaker, despite the decent hardware.
Also, does it play MP3 gaplessly? Sony have long been able to play ATRAC without gaps which is nice, but having to convert all your music to ATRAC isn't so nice, especially when their software doesn't provide a way to batch transcode, except in a way which adds gaps. (Last I tried SonicStage, you'd only get a gapless ATRAC rip if you went from a CD or virtual CD, which made the whole thing a right pain.)