Not the most experienced opinion here, only spent one weekend in my RTT, but those first two nights all my reservations and concerns were removed. I love my RTT.
The largest factor that drew me to it was my pure and simple hatred of ground tents. The selection of a site, spreading and folding a tarp, fooling with those bendy rods. If a ground tent had roots it would be called a Venus Idiot Trap plant. The last time I camped in a ground tent was with a group of friends, and it poured rain all weekend. We had a minor tent city set up, a bunch of tarps strung up, and I didn't get too wet overall, but I had water in my tent when I left despite my best efforts and no visible leaks, and I wadded that wet mess up in my truck and went home. That would not have worked if I planned to camp somewhere else the next night.
It wasn't cold, but it got down to about 50-ish my first night in the RTT, and I was nice and warm in my sleeping bag, a 40-60 degree bag that seemed perfect for it's rating in the RTT. I didn't get cold from underneath, no air mattress but a foam pad. I get chilly on an air mattress anywhere.
I had a little visitor the second night, a big fluffy skunk tooled around my camp not long after I got settled. I unzipped my window, pointed my flashlight at him, and as I had most of my gear stowed away, he wasn't bothering anything, so I slept easy knowing there was little chance of him being a nuisance with me up there off the ground. I really liked that benefit of a RTT. In the same campground area I've heard of them getting into the tent with you from time to time, and a friendly skunk can make for a very bad day once they decide they don't like you no more.
I also have a pop-up trailer camper, and the sleeping experience in the RTT is pretty much the same as the pull out in the camper. A canvas covered flat platform. I actually believe it slept better than the camper, the mattress is a shave thicker in the RTT (I have the Smittybilt Overlander) I also liked using the sleeping bag over fooling with sheets like I usually do in the camper or using an air mattress.
The only thing I don't like, is it's an absolute pain to remove and re-install on my SUV. If my rig wasn't my daily driver it wouldn't be as big an issue. I ran with it installed for like 3 weeks, it's not that hard to deal with, but it does suck gas mileage, plus it gets exposure to the sun and rain all that time your not using it, which might wear out the covers sooner than desired.