I've been thinking about this thread all day since I posted earlier. And I think I might change my vote. I owned a 2000 Chevy with a 5.3. It towed my Jeep OK, but anything heavier was to hard on it. That's why I bought my Stupid Duty (I call it that lovingly). The one thing I really miss about my Chevy is the interior. The seats were soooo much better than the concrete ones in my Ford, and I liked the Chevy dash layout a lot better.
Now, The reason I voted Dodge before was solely for the Cummins. Even a lot of Chevy and Ford guys will agree that the Cummins is the real badass of the three. But, like many have said before, the 'Max is no slouch. So given the ride and creature comforts of the Chevy with the respectable power of the Duramax, I think it may be the better choice.
BTW even a big block gasser is no match for my Power Stroke. I've driven them both and raced my buddy's Chevy BB uphill pulling our trail rigs. He didn't have a chance. If you pull anything heavier than a TJ, diesel is the only choice!