I really adore my Zen; after three grueling years of solid use, a couple of scrapes, and a few drops onto concrete, it still works like new.
The simplicity of the Zen is great, although the sensitivity of the scroll can occasionally catch you out; I remedied this by changing the sensitivity level, which seemed to sort this. Also, pictures can be uploaded onto the Zen and used wallpapers, though unfortunately you cannot view the pictures while watching your music.

Battery life is good, I got consistently 10-11 hours out of it, and the battery life didn't decrease throughout the years and I found the sound quality to be great.

Uploading songs onto it is so much easier than an iPod, simply drag mp3 files onto it from My Computer, and within seconds, they are copied into albums. Also, another nice feature on the Zen is playcount, which I was disappointed to find not on an iPod, as I enjoy seeing how many songs I had listened to, and my 'Most Popular.'

Summary: Excellent mp3 player, if you are not looking for an iPod, that is durable and superb value for money.