We had a 6.5 Turbo in a '97 GMC Sierra.. it was rather bulletproof. It wasn't the quickest thing around, but strap ~12,000 pounds of our boat behind it and it would pull like hell and not gripe a bit. We have since traded that truck in on a Sierra with a Duramax in it, and I have to admit that I am highly impressed. It goes down the road like a gas truck, and it even makes our old 6.5 look weak in handling the boat's weight on mountain roads. IMHO.. if people can get over the GM diesel stigma, the Duramax will be a valiant competitor.
~D.J.~