I have one, it's great. Screen is more vibrant and clear than the Ipod, and movie files don't need to be converted. The 4 hour video battery life is huge too. I got stuck in VT flying standby so I watched Rocky Balboa, Borat, and still had 2 hours left to listen to music on the plane. I have had no problems with it, video or audio.
It sucks needing to bring the dongle with you to plug it in, and it doesn't come with a charger so you have to hook it up to your computer to charge it. Another drawback is the video out is a proprietary design, so you can't just buy a cheap one. Their's is only like $15, but you have to order it from their site. It is the same pin layout as the Imac, though. One other drawback is that most speaker systems work specifically with the Ipod, so I don't know if it is compatible with most speaker systems or not, I just plug it into my stereo anyway.
The Creative Media Explorer is 10x better than ITunes, ITunes sucks shit. It is a little thicker than the Ipod Video, but the better screen and double video battery life make it a fair trade.
I can't really think of anything else, fire away if you have any specific questions.