The only part of the Zen that should ever pose problems is the HDD. Which is replaceable. I killed my Zen after one final drop over a year ago, and recently fixed it (it's for sale in the classifieds here
). The only other issue I've ever run in to with ZVMs are the LCD breaking (mine broke as well as my friends). Otherwise, they'll last forever.
The only thing I really miss about the ZVM is the 60GB capacity (I use a Cowon S9 32GB now). The interface was nice, but I couldn't live without Gapless playback or folder browsing anymore since I've gotten it with the S9.