I'll be the 1st Chevy owner to jump in on this. I have an 04 Chev 3500. 1st I assume they're both diesel? The 05 Chev has upgraded injection system compared to the 04 so that's a plus. Allison Trans, big plus. It's quieter, has more rear seat room (if it's needed for hauling friends or kid or grand kids around after you get set up and head out for whatever). I think the Chevy is quieter inside. Ive only driven a Dodge without a trailer and it was a 3/4 ton. On the plus side, it had a tighter turning radius. For me, a fairly big guy, I have more room in the Chevy. I think fuel mileage is comparable. The Dodge may have some factory warranty left, I don't know on the Chev. I must say, I'm a Chevy man and the Duramax/Allison is a heck of a set-up. The Cummins is good too but if I had to put together a truck, it would have a cummins/allison on a chevy frame and body. I don't think you can go wrong either way.