Yea, well some of the numbers I crunched put it closer to twenty. (Which goes along with what some MS Guy said at E3, but can't think of his name right now.)
It's going to be a fun launch isn't it! Also, early numbers had it about 8 times more powerful. The CPU seems to be running at around the best of the rumors + a whole bunch of co-processors (15!) and I do not know if that includes the 2 extra in Kinect or not. Hopefully, and I think they will, have all this covered by DirectX and the programers will not care which is doing what.
Yea, that diminishing returns thing. Basically, you need to double the power to make it look significantly better, then double that again to make it look better again. So a bunch of power gets eaten up quite quickly. Wasn't the PS3 something like @30 times more powerful than the PS2? Which would make it about 5+ times better - some of that was eaten up by the format going from SD interfaced to HD and progressive scan. But just about anyone can see the games look nicer.
But remember it's not all about hardware power. They are all running different operating systems and different API, etc. It's like a car needs a good engine, but if it has a lousy transmission, it can't use it's power. So it makes it harder to compare PS4/Xbox One.
But for the Xbox 360, yes, I think you will be very please with the power upgrade. (Also, have you tried the new controller yet?)