Nokia Blog - Here’s a video comparing the Nokia N8 with the new Nokia 808 PureView. The N8 seems to have some Belle FP1 style mod going on there.
The N8 is the oldest of the S^3 bunch, so performance difference would be a bigger gap than say, the 701. It might just be the wallpapers, but the 808′s screen just pops out in terms of the vividness. And that’s through video.