I'm with you on this one. I have the smaller 5GB one which is really nice to play around with. If only you could drag and drop without having to use proprietary metadata systems.
But, Sonicstage works well with it, far better than Connect and is a lot more stable. It's not ideal, and you do lose things like Artist Link features, but at least it's reliable.
From a sound quality point of view, I think it's fantastic and I agree that good quality DACs are a must. OK, I do sometimes listen to music on the bus / train / in a noisy environment, but then again, sometimes I'm away on business in my hotel room chilling out and I really value fine music reproduction then! It's nearly gapless - closer to gapless with mp3 than with wma files, although the mp3 performance may improve if you have constant bit rate (all the music on mine is variable so that may have a negative influence).
My old man's after a new MP3 player, and it was searching for info that I came across this thread. He has a Karma and his biggest pet hate is the requirement of using rio manager to transfer stuff, although I did read a java applet thingy and came across red chair manager which I'll take a look at.
I don't have anything against proprietary transfer programs, as I can appreciate certain benefits of handling metadata and keeping a database for fancy linking like the sony player does with Connect. BUT
IMHO it's just unreasonable to expect someone who's very carefully spent multiple hours organising his entire music storage system using directory structure on a PC to then just trash that away because you HAVE to use a manufacturer's own software... That's just lame and poop!
As for other features, I'm not bothered. They can stay providing they don't hinder battery life or cripple the device / slow it down when you just want it for music playback.