Background music: Magnatune artist Curl, used under Creative Commons Attribution-NonCommercial-ShareAlike 1.0. The track is Pure Mix 1 from the album Inner.
A comparative review.
Price: roughly same per GB.
Size: similar. Zen is shorter and fatter. iPod fits in your pocket better.
Display: Zen is physically smaller, but also has smaller pixels, more lines (three vs. two on the iPod), and a few more characters per line.
Formats: mp3 in common.
Media management: both have multiple options.
both have decent navigation, by playlist or ID3 tags
Zen can bookmark mp3s.
Zen can record from an internal mic.
Zen has FM radio but reception isn’t so good.
iPod now has a separate area for podcasts.
iPod has games.
iPod clock is smarter (syncs against PC).
Both have the single most useful control, a lock.
Zen has a hyperactive backlight (good or bad depending)
Zen is 100% touchpad, easier to screw up. iPod buttons == good.
Easy to screw up on both, but your’re more screwed on the Zen.
Fast forwarding slightly easier on the Zen.
Manufacturing quality: iPod wins, but too small a sample.
Overall: iPod wins