I picked up a 2012 Yukon SLT on Monday. It was an Enterprise rental with 19K miles. While the word rental may scare an individual, I'm of the opinion that most of these SUV rentals are probably taken better care of than non-rentals because logically renters have to go out an inspect the vehicle each time it's rented (per the protocol) and make note of any slight concern for fear of being charged on the slightest nick. Same would go for driveability as well. In short (and in reality), the vehicle is scrutinized ten times more than your private seller. How many private sellers scrutinize their vehicles every time they get in it?
If you find yourself looking to trade for used rental, and the vehicle is still under warranty, I would not be too concerned. It appears that others on this thread have already taken the leap without any real concern and have, thusfar, provided positive feedback. All this, of course, is just my .02 cents. Either way, good luck on whatever you decide.