simpler interface

This isn't true. I have no problem using either UI, but I prefer the UI on the Karma to the iPod. If you're playing a tune on the iPod, you have to reverse through all the menus to get to the main menu. That is moronic.

more attractive

I don't really care about the looks. What I do prefer is the size/shape of the Karma. It's very comfortable to hold.

better build quality

That may be true, but I think it has more to do with the materials chosen for the Karma.

I actually wanted to hear from a zealot

I actually am an empeg zealot. I would probably buy anything they make over their competitor.