These are pretty nifty little gadgets and a whole lot cheaper than those shiney iPods. Of course they are cheaper for a reason, and that's not just because they aren't made by Apple.
They have less storage space for starters. Although they are advertised as having 512 MB of storage, you can only use 493 MB. Presumably 512 is marketing-speak for any number between 257 and 512. Whatever, it's still more than enough space for me.
The buttons are tiny, so navigating the menus, skipping songs, or adjusting the volume without fishing the thing out of your pocket and looking at the display, is pretty much impossible.
Still, I'm pretty happy with it. Now if they could just make these things BIGGER with buttons designed for human fingers…