Stability - Im sure Ill get some flack over this but the iPod is more stable than the Karma. The Karma is much, much better than it was in the beginning but it still is not as stable as the iPod.
The Karma just provided music for my role playing session tonight, with quite a bit of use on the now and next screen, and in and out of the music selection area. Worked fine.
Same situation on an iPod usually has it locking up once during such use, even though the iPod had less features being used to play music. The ability to reorder the music coming up on the Karma was very useful, something the iPod couldn't do.
And while not stability related, in the 6 hours I used it, the Karma looks to have about 65% of the battery left. The iPod, well, the owner keeps his power brick with him for these sessions. True, his iPod is a year old now, but even if the Karma drops 50%, I will get about 8 hours of use out of it.
I'll post my review of my Karma in a few days. Was hoping to test it on the motorcycle, but we have snow on the ground again. Yesterdays 60 degree weather was an isolated event it seems for now.