As someone mentioned earlier, the Nissan XD Cummins is going to be a very tough sell to the in-the-know towing crowd (i.e., most rv.net members). It offers minimal value in terms of raw towing performance (based on the numbers).
I had high hopes for this truck about 6 months ago. The Nissan nameplate, the 5.0 Cummins' with projected 20+ MPG's and the projected 2000+ lbs. of payload. From all accounts, they're only batting .333 on these key issues. Looks to me like enthusiasm has dropped off significantly at titanxdforum.com . . . the reality of its true capability appears to be sinking in. Definitely much less hoopla there vs. what the Ecodiesel forums were getting about the same timeframe of it's release.
IMO the vast majority of Nissan Cummins buyers will purchase based on the Nissan/Cummins nameplates and style, and not much else. Mention payload and you'll get a blank stare. It remains to be seen if there's enough of these type of consumers to sustain decent sales.