I've towed with it only a few times, but I'll give some feedback.
I helped a friend move about 30 miles towing a full 12' uhaul and carrying his bed and some crap in the truck.
With high hopes, due to the 305 lb ft that this motor has, I set out in hilly stop and go traffic.
The truck has "adequate" to anemic power. The tranny got up to an unsettling 221 degrees and it was only about a 50 minute drive. It felt labored and strained. The Chev is about 5300lbs, 3.42 gears, 4x4, 4.3, 2017, stock.
For the sake of comparison, my last truck was a Nissan Frontier 4.0 4x4. It had 3.13 gears, 33 inch mud terrains that were north of 70lbs at each corner, and about 800lbs of off road armor. (Unloaded at the scales it was about 5150lbs).
When I moved with this truck, I traveled a greater distance, had a full, heavy load in the bed, a passenger, a much more packed 12' Uhaul trailer, drove it hard, and the Nissan didn't feel labored. The engine felt like it could've taken another 2000lbs.
This comparison isn't completely fair, because the Nissan engine was tuned with a Superchips Cortex for 87 octane, but it does give perspective.
Maybe when this beast is out of warranty, I'll tune it and see if improvements become apparent.
Tomorrow the Chev is towing about 1300lbs, should be easy, I'll report what happens