I drove one for about 2 years, best truck I've ever owned. My father also used it to tow his 28 foot boat. I suggest you get a pick up and not the avalanche. The Avalanche did not come with the Allison transmission, but the pick ups did. Makes a huge difference. Also I did average 11mpg towing or not lol.
I'm not worried about mpg. I don't have a long commute. I just want a toy to piss off my coworker. Lol. He has a 2013 Harley f150 with some loud, shitty exhaust. An 8100 with straight pipes should silence him. LOL
if I wasnt stuck on ls powered vehicles I would have found my truck with an 8.1 and Allison.
my buddy has the same truck as me with it and it does tow like a champ. he put long tubes on it with straight pipes literally going straight back from each header. its the only vehicle ive ever liked straight piped. rumbles like a damn Harley at low rpms