Towing with an Explorer, Highlander or 4Runner-experiences?

Also for the record, my best friend bought a 4Runner, and she absolutely hated it. She lives in the mountains and said it was a total dog going up the inclines...and that's without towing anything. So much so that she traded it back in a couple months later for a new model of her previous vehicle, a Lexus. I'd imagine a Highlander would be even worse.

ETA: The in laws tow a 22'ish ft travel trailer and a boat (not together) with a Sequoia and are happy with it.