Well, I couldn't wait to try it out so my buddy and I took his 22' bayboat to the gulf this weekend and I pulled with my 5.7 Crewmax 4X4. Here are my thoughts and opinions for those interested.
1) Boat + trailer + crap = approx 5,000 lbs
2) Acceleration from a dead stop was effortless. Didn't really tax the truck at all. The 6 speed is a godsend in this department. My old Chevy really had a hard time getting up to speed on the interstate with this boat, but the Tundra hardly blinked.
3) Highway power was good if not excellent. The truck would easily hold 75 mph in 5th gear with little effort. 6th gear was not useful at these speeds, but the automatic transmission did not make any effort to upshift which was nice. Even in the manumatic mode, the truck knew better and would not upshift even if you put it in 6th. On slower speed highways under 60mph, the truck could and would shift into 6th and hold pretty well.
4) Tow-Haul mode worked well. Truck did need to downshift to 4th when cruise control was on going up steep overpasses, but the truck didn't thrash like my old Chevrolet did when downshifting.
5) Ride quality. Very good. All of my passengers made comments about the trucks good ride while towing. Actually much smoother with the boat than unloaded.
6) Truck stability. Awesome. This big truck was not being steered or "manhandled" by the boat the way my smaller Chevy used to be.
7) Brakes. Fantastic. Maybe even perfect. No fade, no drama.
8) Gas mileage. Averaged 10.2 round trip, mix of highway and city. Not sure if this is good or bad. Friend who owns the boat claims his Suburban gets 11-12 with same load on same trip. But the Tundra is new and not broken in, so I think it is OK. In my personal experience, gas mileage usually improves until more than 5k miles.
9) Misc: The 4 pin and multipin connector is a nice touch. I hated the "adapter" that I needed on my chevy to connect a 4 pin because I never seemed to have it handy when I needed it. Also, backseat room was applauded by rear passengers and appreciated on the long ride home after a hot day on the gulf.
10) Overall. I came away pleased
. The truck did what I expected and a little bit more. I would feel good towing up to about 8000 lbs any distance. Above that I would relegate to shorter trips, simply to prolong truck life. If you plan to pull a 12k trailer, get a Diesel. For most boats, small to medium travel trailers, etc... this truck is awesome.