I've had the YH-920 for about 2 weeks now and I have gotten to the point where I have a good idea about its weaknesses and its strengths. For the people who are having trouble getting the YH-920 working, the issue is not with SP2 as I have service pack 2 and it had no problems recognizing it. Any issues you are having with it being recognized involve not updating the drivers for your USB ports. Check your manufacturer's website for either an allinone driver for via chipsets or a usb driver update.
To begin, your choices for adding songs to the player are either napster or windows media player 10. If you are primarily adding random songs but not full albums, use windows media player as i found it both simpler to use and faster. If, however, you are adding albums to your player and you want them to play in track order, use napster. Windows media player sends files to the player and uses their track name in the id3 tag to determine the order of the album which causes the album to play in alphabetical order versus track order. Napster arranges albums by filename, so if the album is in the correct order on your hard drive, it will transfer in that order.
As for the player itself, its very simple to use once you find out its functions. The manual is terrible for explaining basic features such as fast forwarding tracks(hold >>| button) and adding an entire artist's songs to a playlist(hold the select button). I figured out how to do these by playing with the thing, but it should have been explained in the manual.
As for sound quality, its on par with the ipod and other players, but it greatly depends on the quality of the song. Anything less that 128kbps for mp3s sounds bad. I suggest any albums that you rip to your hard drive be at least 160kbps or 192kbps.
You are given the option of chosing songs by genre, artist, or title. Again, if you are transfering a lot of songs, make sure to check the tag information for the songs, otherwise you'll end up with 1 artist being read as 3(ex. 2-pac, 2pac, tupac). This is no different than any other mp3 player, but its particular important once you fill up 20 gigs of mp3s.
So far so good. The only issues I have had with the player is battery life and slowdown when loading up artists. I have filled about 18 gigs with mp3s, so when the artist list loads up, it takes about 5-6 seconds to work. Also, if you fill up the hard drive, it has to spin more to get to other songs. Battery life for me has been around 7-8 hours, which isn't terrible, but its not as good as the zen touch.
All in all, the more i get used to the player, the more i like it. I have little to complain about with the hardware, however compared to the relative simplicity of itunes, the software needs some improvement. If you are willing to get used to the software, the player is fine.