The more photos I see in this forum the more I am convinced that a really good photograph has more to do with the photographer than the equipment. We have at least one photographer on this forum that shoot a CoolPix and his photographs consistently are better than some of the people on here that shoot the high end FX format cameras.
We love out Nikons around here and that is great but most manufactures of cameras today all have their good points and bad points. It all comes down to personal preference and what you get used to.
Don't have time to watch, but from what I know about a lot of pros they will shoot what you give them. Having sat through one of his talks I know the praise he has for the D600 and D800 sensors. I also know that he's not beyond lending his name to sell something.
My brother shoots with a pair of 1D's for work and a couple 5D's as well, and when we sit and talk there is room for praise with all of it. For Canon it's a coup. For me, it's no big thing.
Shoot what you love - love what you shoot.
I'm sure Scott is pocketing some serious digits for his public switchover.
While I don't know for sure whether he has to send it back or not (I doubt it) I do know he has to give his opinion about the camera.
From another aspect, Scott Kelby must work to not alienate Nikon users in this switch, and I believe that he and his team will accomplish this. There's too much at stake to risk losing some of his Kelby Training clients over this.