I bought the Rio Volt MP3/CD hybrid. It kicks ass in the fact that you can burn a MP3 CD with 11 hours of music on it. With two regular AA batteries I can listen for about 15 hours. The only problem I've found is that you have to have a burner to make MP3 CDs which most people have, its the size of a CD player so its not as small as one of the chip kind, and when I'm running on the treadmill and I get up to a faster speed the impact skips it, even when I have the 120 second skip protection on. After that 120 seconds of buffer is up, it sounds like shit. I started putting a towel under it and it works fine.