Setting aside Rio's thickness claims for now, I'm looking at those pictures and it looks to me like Karma is overall much smaller. I don't have an Archos, so I don't know much about it, but do you often take the bumpers off in normal operation? If not, it's not really fair to compare their dimensions by taking exterior pieces off of one (as I said, though, maybe you can take them off and bumper-less is typical -- i don't know). Also, does the Archos fit in your pocket? Looking at the pictures, I would imagine probably not. Just out of curiosity, what's the battery life like on the AA's?

ms