I have a 2010 Tundra with the 5.7 and LOVE it. The only downfall is low payload rating. All half ton trucks suffer from low payload though, so if you are looking at a half ton you need to pick your poison.
The biggest advantage with the Tundra for me was the engine. Toyota will put that 5.7 liter V8 in any trim level Tundra you want. I looked at the GMC twins with the big 6.2 V8 but you have to get pretty high in trim level (and price) to get that engine. I looked at the Ram with the 5.7 Hemi, but payload was much lower than the Tundra and I was still uneasy about Ram quality, especially with the bankruptcy issues. Ford's 5.4 was a solid engine, but uninspiring to me at the time.
The Tundra offered the best engine in the base package and respectable payload to meet my expected needs for 10 years. I tow about 4000 miles a year or less and the Tundra is used for other reasons the rest of the year. I couldn't justify the weight or cost of a 3/4 ton truck, nor did I have the NEED nor expected need for that big of a truck.
My next truck will require more payload, something the Tundra doesn't yet offer. I am very happy with my Tundra and have ZERO regrets. Plenty of power, feels stable when towing and gets decent mileage for a gas engine when towing (about 10 mpg).