Would have been nice if the older (VP7?) codec had been included on the N900 version. As that's the blindingly obvious thing to do, I'd assume that the N900 didn't have the CPU horsepower to do realtime VP7 encode/decode, whereas H.264 can be offloaded to hardware. Also the proprietary VP7 has traditionally been Linux-hostile, but with video calling on the newer Linux skype client I doubt that was the obstacle.