The Titan's not so new that it's an unknown but they've never caught on. That causes me to wonder.
The 2016 Titan is a complete redesign. At this point an unknown from a company with a less than stellar reputation. I don't think the older version was really that bad but they really never caught on.
A friend of mine is a K-9 officer (blood hound) with the Sheriff's dept and drives a 2012 Titan 4X4 for work. Fuel mileage sucks, but he ain't paying for it and with over 100,000 on it has had no major problems.
Unless the price difference was significant I'd have a lot more trust in the Tundra.