Hi,1
I own the first-generation SP100 Riovolt. I've had it for over a year now and it's still working great.
I find that I am no longer using it as much as I used to for a few reasons. First, it is a bit bulky. It weighs quite a bit more than my smartmedia mp3 player and is bigger so it's not as convenient to take around. Another thing I've noticed is that an entire CD of mp3s is totally overkill. There is no way that on one sitting you would listen to even close to the capacity. While it's nice to brag to your friends that you have so-and-so hours of music on your mp3 player, it really isn't too practical. Although it is nice to be able to have a wide selection without changing cds all the time.
The player sounds pretty good too. However I read reviews before I got the player that all agreed that the earbuds that come with it pretty much suck, so I never even tried them. But I've found that the quality of the playback is good enough.
Hope this helps.