I had a chance to sample the Nissan Titan XD with the new 5.0L V8 Cummins engine. I have to say that first of all, the truck was awful. Secondly, the transmission needs to be programmed better. Thirdly, the engine is actually pretty good!
It was smooth, power was good, torque was good down low. Turbo lag very minimal. Cant even hear the turbocharger at all.
Downside was the transmission is awful. The throttle response was like when a car is running out of gas. It cruises happily in 6th gear at most speeds over 50kmph but when you apply throttle it grabs two gears so there is a definate pause. There wasnt really any notible engine braking either, in tow mode it shifts down but it more or less coasts. Even in manual mode there was a delay between when you put your foot down and the engine starts to take any action.
And the cost? For a Loaded Titan XD you can roll out of a Dodge dealer with a King Longhorn Platinum Dually decked with accessories.
Focusing on just the engine alone, I would liken it to a 6.4L Ford engine with less of a top end power band (and less power). The powerband was similar, but the throttle response was awful, which I think is mainly attributed to the transmission programming.