I almost ordered one just to toy with, since its so cheap, but a quick scan of reviews landed me at gear.ign :
http://gear.ign.com/articles/356/356405p1.html
"I think that the software further slows the transfers. You Mac users will be happy to learn that the Riot ships with iTunes. You PC users, however, will be depressed to discover that SONICblue decided on Real Jukebox for the software. Real makes the worst software ever. Naturally, as soon as I installed the program, it started taking over everything in its path. My hatred toward Real has helped me to develop a natural resistance to it, so I can deactivate everything quickly. I feel bad for those of you who have to put up with the software, though. And yes, you must use Real Jukebox for transfers. You cannot drag and drop files onto the Riot, which is a real drag. This also means that you cannot use the Riot as a generic portable drive."
Real is, in fact, the worst software known to man, being just a hair's difference from classification as a computer virus. Solutions like this are exactley why a company will go bankrupt.
If you're gonna buy it, load the music up on somebody else's computer. You may never get Real off your own PC. And, its gonna take some time. IGN found a 5mb file takes 15 seconds... so figure about 15 hours to load it up. DAMN.
***EDIT***
OK, apparently you can actually use Windows Media Player 9 to load tracks onto the player. I found this :
"Go to Microsoft and search for "Rio Riot" drivers. You should find something with the following description. ...
Windows Media Player 9 Support for XP and Windows XP Plus! Digital Media Edition's Portable Audio Devices Power Toy
Version: 1.86
Date: 3/04/03
File Size: 271 KB
This file is provided to owners and users of the Rio 600, 800, 900, RioRiot, or Nike psa[play for the express purpose of using Windows Media Player 9 to transfer music tracks from the computer to the Rio players and supporting Windows XP Plus! Digital Media Edition's Portable Audio Devices Power Toy. Please note that if you would like to add support for your Rio player to Windows Media Player 9, you must have the public release of Windows Media Player 9 installed to use this upgrade.
To begin the installation, expand the contents of the .zip file LegacyRioSupport_MyAudio_WMP9.zip to a known directory. Browse to that directory and double click on the Sbdrvsetup.exe file and the installation will begin."