Lifted jeeps aren't as comfortable... Lol
In my opinion, buy a stock jeep. For the simple reason, you know what's been done and not done to it. Then, if u want to throw a little lift and some tires on it, do it. Besides, in my experience... A stock jeep most likely hasn't taken the beating that a lifted one most likely has. (I.e. beach, sand, salt, mud, rocks, trees, etc.) and I think hooked was referring to tire cost, fuel mileage, and upkeep in general being cheaper for a stock vehicle.
As far as what to look for... Everything you would normally look for. Rust in the body as well as underneath (suspension, frame, drivetrain, etc) leaks, loose fittings, bearings, linkages, drivetrain parts. All of the normal stuff! Lol
I hope that helped