Tough choice!

The iPod is very mac-friendly, and since you're a mac owner, it might be a no-brainer.

But then there's the battery life question. If you're going to use it in your car and on airplane flights, the 15-hour battery life of the Karma might make all the difference. I'm not sure what the exact battery life of the iPod is, but I get the impression that the Karma is about double the iPod. If your flights are frequently overseas flights, the Karma might be your only option.

But remember that if you use the Karma with your Mac, you can only load tunes with ethernet, so you won't get the speed benefit of USB2. Ethernet to the Karma will be faster than sending tunes to your empeg was, so you'll still see an improvement of speed, but it won't be nearly as fast as firewire-iPod or USB2-Karma from a PC. Also, you'll have to find a friend with a PC any time you want to do a firmware upgrade on your Karma (the upgrades only work on USB2).

But the features of the Karma are pretty darn cool, certainly you can do more stuff with organizing and selecting your music than you can with the iPod. And there's that battery life to think about still...

I'm guessing you don't buy your music from iTunes, so AAC support isn't a critical issue for you...

If you have a lot of custom playlists on your Empeg, you can (with Mike Schrag's utilities) copy those directly over to the Karma, hierarchy and all. Maybe that is the clincher for you?