Absolutely no mechanical failures.
The front suspension is mushy, and often I bottom out when traversing a pot-hole ridden street. This makes a really ugly thump sound, and I just cringe all over when it happens. I will be changing the shocks to the Toyota Racing Development (TRD) Bilsteins when I can afford it.
The floor of the cabin should be two inches deeper to accommodate a more vertical seating position, which most trucks give you a feel for. The truck cabin is too car like, and it takes getting use to. The leg room is adequate, but could be better.
Of course the back seat is not for adults, thus this truck is not a "crew" cab, even though it has four doors. The Tundra should be stretched lengthwise by ten inches to accommodate a larger cabin and a full 6' 6'' bed. The bed is only 6' 3''. I am sure stretching the wheelbase will improve the payload and towing capability as well, as it would prompt Toyota to add a stiffer suspension to the rear wheels.
If the Ford Superduty or Chevrolet Silverado could be built to Toyota's benchmark quality, I would buy Ford or Chevy's. However, Toyota still builds cars and trucks for the Japanese-sized man. Luckily, I am only 5' 10''. My 5 foot tall oriental wife loves the truck, so we will keep it for a while.
For Ford and Chevy to build their trucks to the standards of Toyota would mean making them lighter and weaker with less power and weaker suspensions. They've been making trucks for over 100 years! I think they know what they're doing!
Just keep believing that you Tundra is quality. The Tundra is a problematic model, which Toyota rushed to put out, without doing their homework, to see how much mileage they could get from it on their name. I guess it worked, because a lot of people seem to have bought into it. Toyota has no doubt made some quality products, but not this model. In fact, they have made some real dogs recently if you want to objectively take a look at some other reviews. You will have problems with this truck eventually. The real quality trucks are listed on this site under Chevy and Ford if you are interested.