i got an hd go pro about 2 weeks ago and i took some clips. 720P @ 60 FPS http://www.youtube.com/watch?v=i8lkfjU1dxs 1080p @ 30 FPS http://www.youtube.com/watch?v=ktj2KeKY2jo 1080P @ 30FPS on windshield http://www.youtube.com/watch?v=BB6TOeGtuqE So far impressed with 720 @ 60fps, it's very smooth. 1080 is nice too but theres a bit of artifacts due to only being 30 fps. All in all its a great camera and BIG improvement over the regular go pro.
FYI, the 60fps mode is smoother, but also Allows you to do slow motion stuff. The more frames per second (fps) the more you can slow the video down and have the video looking smooth. Record yourself clapping in both modes, then slow both clips down to the same speed and you'll see what I mean