I actually own a Zen, and use it daily. Put is simply, it is a disappointment.
First of all, the device uses MTP to link up with Windows, which requires Windows Media Player 10 or above. In other words, you can forget about other platforms like OS X or Linux. There is an open source third party software for Mac, and it works reasonably well, but I can say the same with Linux. I have a Ubuntu Linux laptop, an d the software on the repository did work with my Zen. A quick search on google showed I need to manually compile the source and override some default settings. This is just a bit too much for casual Linux user (the very same reaason I went to for Ubuntu for the ease to use reason)
Secondly, unlike iPod which you can at least see and use the device as a mass storage. This is not an option with Zen because of the MTP protocol it uses. So if you want to use the Zen to move files about, you can forget that idea.
Thirdly, Zen was sold as a video player as well as a competent mp3 player. Well, Zen is very picky on the video format and size. If you have a library of DivX files, and you think you can simply play it on Zen, you will be disappointed as I am. It only plays DivX video at 320x240 (can remember the exact horizontal resolution) with very strict encoding condition, i.e. you need to recoding your videos to play on Zen. In addition, I found the video and audio often out of sync (I am already using the latest firmware from Creative)
Honestly, if I know Creative had changed the way its players linking up a computer (using MTP), I would avoid it like I avoid iPod in the first place.
If I really was an branded player again. This time I would pick up an iPod due to its years of refinement. I guess iPod being the top of mp3 players for so long is for a reason.