We just returned from our inaugural camping trip with ours and LOVED it! I suspect you will too when you get it.
Our 2011 QX56 (no longer identical but still similar to your Armada should you use that) towed it just fine with the Equalizer Hitch and Prodigy P2 brake controller. We only packed a light load until we could get to the scales for a reference point. We weighed it on our return trip with all passengers and a full tank of gas. All of the axle weights were well below their max. Scales were backed up so we will get tongue weight next time out.
I suspect the main difference you will feel versus your popup is the suck in/then out when a tractor trailer goes by. This is just the nature of towing something so large. We were told to stay alert and pay attention to what is coming up behind you so that you have both hands firmly on the wheel when it happens. We did as told and had no problems. FYI... we also invested in the Camco Tow-N-See Mirrors and were very pleased with their performance. They were the only choice for us due to the camera system on our TV. We were leery of the suction cup nature at first but if you follow the directions exactly they will stay on. Just don't over-tighten and strip the mechanism. We used ours on the interstate and they stayed on the whole trip!
Hope you get yours soon if you haven't already - enjoy!!!