It is a beast, it has alot of compatibility with digital music files but the damned thing is too big (dimensions). It is bigger than the Zen, and the Zen is alot bigger than the iPod. On paper it doesn't look that big but in real life the Zen is a brick compared to the iPod. Not bad though, 100GB for $450, that is pretty cheap.
It doesn't look much bigger than the old walkman's. At the most, the discman's. Granted, that is bigger than I would like to carry, but I could see the use in it. Especially if you could hook it up similar to how Alpine does with the ipod. Stick it in the glove box, never touch it.