Armada before 2008 has questionable 4x4. After 2008 it has AWD derived from the ATTESA system (skyline). That's about the only nice thing I have to say about it. If you do get one, first thing you must do is stillen supercharger. But it will still be slow and boring.
But if you're going to do that get an escalade and go see hennessey. Waaaaaay better no question. Not even comparable...
You might complain about repairs on your yukon, but the parts are cheap and easily available, and every shop knows how to fix it between the silverado, sierra, suburban, tahoe, etc they make millions of them. With the armada they are rare and expensive and so you better make friends with the dealership.
I think nissan is discontinuing them anyways. Too big and nobody buys. One thing people might not know they think the QX56 is based on the Armada (based on the Titan), that was only true until 2010. Since 2010 the QX56 is based on the pretty badass Patrol vehicle, which rivals the land cruiser in some parts of the world. Go test drive the infiniti's very seriously before you get an armada.
And then forget about this terrible hypothesis, and get a Denali or an Escalade. Or get a newer Tahoe LTZ. You'll save a few grand and they are just as nice but not as many bells and whistles to go wrong.