Well this is pretty much all I needed to see. Apparently I'm about to become a Nikon-shooter.
The only thing I will really miss is my 70-200 2.8 IS II, but I have heard that Nikon's version is equal in IQ.
It is, but there are a couple of usability issues with the Nikkor vs the "L." First is the focus breathing issue. At minimum focusing distance, the Nikkor has the angle of view of a 135mm lens. The difference is very noticeable.
The "L" behaves a bit more like a unit-focusing lens in this regard. Such dramatic focus breathing in a $2,500 lens is unacceptable to me.
And the Nikkor's lens hood is very poorly designed. You cannot set your lens down on the hood, like you can with the Canon.
I was briefly considering a move, too. Between the cost (nearly all of Nikon's professional lenses are more expensive than Canon's) and the issues with this lens and the 24G, in comparison to the equivalent "L's," quickly put that thinking to an end.
Not to mention having to learn a completely different user interface, Nikon's poorer reputation for customer service, etc.