I just bought a '04 Dodge 2500 Crew Cab 4x4 auto. I wasn't looking for quiet, but it is very quiet compared to earlier diesels.
I drove all of the big three before buying, to sum up my opinions (not to start a brand name flame war /forums/images/graemlins/grin.gif)
Ford - The problems some people had with the 6.0 scared the pants off me. I know there are some out there with zero problems, but there have been lots of buy backs, engine replacements & reflashes. That was a red flag to me, the torque shift transmission isn't without its problems either. The crew cab on the Ford is enormous. Handling was loose and it took a 40 acre field to turn it around.
Chevy/GM - The smoothest ride of the bunch, but the General is awfully proud of his merchandise. The best I could do was about $4000 higher than Dodge. It seemed like more of a beefed up 1/2 ton than the HD Ford or Dodge.
Dodge - I was surprised at how well the new Dodge compared with the competition. The Cummins is the most trouble free diesel of the bunch. The new 48RE transmission, although still a 4 speed is a big improvement over the 47RE. Not too many complaints over it so far. Drive is solid, brakes seemed to be the best to me. On my crude 0-60 test it was right up there with the others. Best of all, it was $2K less than the Ford, $6K less than the GM. (disclaimer -best dealing that I could do, you may do better)
JMHO,
Bud