It depends.
Scenario 1:
If it's an APU ONLY, it might be 4X PS3. Which would make current gen games running at 720p 30fps run at 1080p/60fps.
Scenario 2
If it's an APU and a discrete GPU (8850), it will be 12-16X PS3. This would be the Batman we need.
I'm with GoFreak.
This last rumor said that will be a custom APU, so if they want they can add a way more graphical horsepower than the current PC APUs.
It would mean less cost, noise, space and heat than a discrete GPU.
As they stated and made with Vita, they won't repeat the $599 with massive losses fiasco again, they will made something powerful, maybe not high end, but affordable.
MS stated in the leaked doc that they aim to make Durango as powerful 5x to 8x 360 ducktaped.
So if Sony makes Orbis as powerful as the same number of PS3 ducktaped (let's say 7x) they're on the right spot for me.
Which obviously would be way more powerful than current gen consoles and the farmer with a shotgun.
And remember that console games always looked way better than PC games running with the same specs, because in consoles they are optimized to a single (maybe 2) hardware SKUs, while PC games must run in a lot of different configurations so they need way more powerful hardware to get the same or better results than consoles.