I've got a Zen Vision M, and its great, though it picks up fingermarks/scratches on the front plate rather easily, and is why I've ordered myself a silicone skin for it with hard protection for screen.
The quality of the audio is amazing, though the battery life could be better, and ran from my real life tests, get around 13 hours 17 minutes. 42 minutes off there stated time using 192kbps instead of 128kbps and having volume at 13-16 rather than around 8.
This is the first Zen I've got, and have nothing bad to report except for the buggy software you use to copy tracks to it, that need sorting out ALOT!
Make sure when you get it, after recharging, plug it up to USB and do a firmware update from the creative site. You'll find a firmware that will fix alot of things most likely.