Congratulations! You are going to absolutely love that truck. And if you think you like it now, wait until you tow with it; the low end torque of the inline 6 makes the biggest passes a piece of cake, and the 2 stage exhaust brake makes descending them a pleasure as well. My fiver weighs 16k lbs and I find myself having to give the truck throttle descending a lot of passes because it slows us down that much :B And it gets 11-12 mpg doing it.
I totally agree with you that the Cummins is superior to the competition in several ways including long term maintenance, repair costs and durability. The CP3 high pressure fuel pump reliability vs. the CP4 is one of the most key areas where it is superior. It is very easy to find many, many examples of high mileage Cummins trucks, even in the 4th generation. I plan on keeping mine for 20 plus years so this was of key importance to me. The Ford and Duramax may be slightly quicker off the line and climbing passes, but I am not in a race.
I agree with MeAgain that you should seriously consider installing the fifth wheel prep package in your truck. I have read about several people that have done this without issue and Chris was the latest one. He has some great pics and a good description on how to do it as well. My truck came with this package and it's great; there is no drilling in the bed and everything comes out very clean and easy when you want to haul something with the truck. Having the rails in the box is a PITA compared to this system. I agree with him on the Demco picture frame adapter as well because it allows the adapter to be removed with the hitch still mounted on it. I have the factory Ram adapter and the locking arms are such that the hitch must be removed to remove the adapter.
Please keep us updated on your hitch progress and of course, your first tow ;)