I'm happy with both my Titans (other than fuel mileage). I traded a 2011 F250 diesel in on my Pro 4X earlier this month. I enjoyed driving my wife's 2010 LE so much more than the F250 and the Titan meets my towing needs. However, I've gone from averaging 16mpg to averaging around 13mpg. Just be aware of that when considering a Titan. I knew it going in but many people are surprised by the mileage.
apples to oranges, really. MPG on an oil burner is almost always going to be better... There's times I think about how much $ in fuel I would have saved over the last 8 years had I gotten a diesel instead of the T (I was also looking at a used, no frills, CC longbed F-350 when I bought my new titan) JUST
due to idle time. But in the half-ton world, I have yet to meet anything that tows as comfortably and intuitively as a Titan. Get into 3/4 and one-ton realms, and there's no comparison. My wife's 2500 suburban with the 496cui, gets comparable mileage, and can out-tow the Titan in any conditions, BUT the comfort factor just isn't there (GM seats torture me). My 89 F-350 dually (7.3idi) isn't fast, quiet, or comfy, but it will out-tow anything that has a nissan logo on it including a 35 NV... but after a run, you know you WORKED to drive it. The other factor, is that anything needing to be fixed on a Powerstroke is going to seriously traumatize the wallet, where the VK56DE is pretty middling cost-wise. From my experience, the higher fuel costs are drastically offset by the lower maintenance costs when going ford/gm/ram vs titan (0 experience with Tundras), and especially going diesel vs gas if you don't have the need for the sheer grunt and torque of a coal-thrower.
Maybe I have an odd POV on this, because I regularly roll Kenworths and Peterbilts that make any pickup look like fluff when it comes to power and towing capacity (And mileage? roll a diesel that holds 300 gallons and averages 5-7MPG up to a pump on your dollar..talk about pain...), but to me, a diesel is all work and no play, where a gas can do both. When you are talking need for dragging, nothing beats a diesel (Except maybe, a bigger diesel), no matter how much more comfortable it is, because preference and feel-good, is far lower on priority than basic function and ability. When you have a workhorse that is also a daily driver and a recreational ride, you have to balance, and the Titan does that very well.
Bottom line, don't get a Titan to be a heavy duty tow machine, but they are OUTSTANDING light duty tow machines. If you need to bump up on towing duty, you will sacrifice some comfort for function..it's just a basic fact of trucks in general. A Volvo N-14 cummins with a ten speed is really comfy to drive over the road, even more so to sleep in.. But it certainly isn't going to compete in sheer grunt to a day-cab tandem/tandem flatbed with a 21 sp and a C-25 Cat motor. The former is a cruiser, the latter will beat the hell out of you, but can haul the volvo, with load, and then some, anywhere, on or off-road, without a strain. as I'm fond of saying, it's about picking what suits your needs and your a$$, not about brand or popularity.