Is it as good as a CD?
I'm just going to have to listen to one of these things some time and see what they sound like. There's no denying the convenience and portability factor.
It all depends on the file, on my PDA i have CD quality if I want it. (usually only for certain songs)
As good as or better, but definitely not worse. Most files played from a CD in your computer are at 96 to 128Kbps. All of mine in my iPod are at 160 or 192Kbps. You will hear that difference quickly.
You can rip your CDs for that bitrate, and the iPod will play it just like that. Sometimes, however, ripping a CD at a higher bitrate won't make a bit of difference, especially with older CDs.