I bought a 40 GB Zen Xtra, played with it for a couple days, then returned it. I now own a Karma and wouldn't think of going back.

The main reasons: The Zen was so darn wide that it just didn't feel comfortable holding it in my hand. The various buttons were placed in such odd places on both sides that you really had to use two hands to operate it.

Finally, and this was the real deal-breaker for me: the scroll wheel mechanism on the Zen is pretty bogus. Very hard to scroll things quickly, and pressing the scroller in was difficult to do correctly since you have to be pressing it in at just the right angle. It just wasn't fun to hold and use! Within about one minute on the Karma I felt like I'd been using the scroll wheel and Rio Stick my whole life.

Other reasons: The build quality on the Zen is just not nearly as solid and "finished" as the Karma. I personally preferred the look and feel of the Rio desktop software. I think the Karma sounded just as good as the much-talked-about sound on the Zen, and in my opinion the Karma actually sounds better.

That, plus, if you really do the math, and your CD collection is not wildly monstrous, then 20 GB of music will be more CDs than you'd ever care to feed through an encoder.