We had a 2000 Tundra that did a wonderful job for us. We moved and when it was time for a new one, the Titan pulled more weight so we got one. While the Titan was a wonderful truck, it's just not a Toyota. This new Tundra is just plain gorgeous and I anticipate performance and comfort on our cross-country journeys while pulling a trailer.
Ride, reliability, resale.
Extendable side mirrors, which is the one feature that the Titan had that the Tundra doesn't.