All things and opinions considered, let's imagine Nikon's camera is actually better for your
particular needs, you'll take better pictures (and will be able to make more money from them!), alright, and you decide to switch to Nikon; you sell all your stuff and buy new lenses, flashes, filters and everything. What if in 2015 (or whatever year) Canon comes up with a 5D Mark IV that's better than the new Nikon D900? Would you switch back to Canon then? I mean, neither Nikon nor Canon (nor Sony, nor whatever brand) will have the best all the time; it's kind of a cyclic thing, I think. This may be Nikon's year; next it'll be Sony's, and then Canon's, and then Nikon's again... In my case, my pictures are not better because of me, not because of my camera, and I'll stick to Canon just because I started with it, no other reason.
There are millions of folks out there with equipment better than mine, and I just don't care. Sure, I wish I could afford very expensive stuff, but I have fun with what I have anyway. I think we're in a time we can't stand not having the very best; second best just sucks. Maybe we all should think a little about it.
I'm sure it's not about having fun, it's about earning a living, too. It seems to me you're doing fine with what you already have, and I don't see much room for improvement from switching brands. Will you make more money if you switch? Or is it about having the very best?
Well, that's just the way I think. People may disagree; I'm alright with that...
Go have fun! Save some money you'd spend switching brands, go visit some interesting country and take nice pics!
That's what I'd do!
Nice work, by the way!