To clear up a few errors in this thread, the High Output version of the Cummins was 305bhp and 555lb/ft. It was the 610 which had 325bhp and 610lbs and was introduced for MY2005.
Also, the rear axle is the AAM1150 like GM used on their HD pickups, not Dana.
My take on the current trucks are that the new for 2011 GMs are tremendous, with the SRW 1 ton rated at 11,500lbs GVWR and the Dually at 13k. Strengthening of the Duramax and Allison internals plus bigger brakes, exhaust brake and all new frame put them to the top of my list.
I currently drive an 08 F450 pickup, 4x4 Lariat trim and 78,000 miles since new. Love the truck and regularly tow my backhoe meaning I'm just a hair below the 33k GCWR. My complaint is the 6.4 lacks the low end guts (peak tq is 2000rpm) of the dmax (1600rpm) and cummins (1500rpm)while a 6th gear on the Torqshift would be great on the highway. Ford improved the powertrain for MY11 and if it proves reliable I may get another ford but I'm totally put off that to get a true F450 I'll need to order a Chassis cab and build it up. The MY11 F450 is now just a rebadged F350 with a widetrack front end.
My Dodge was great, but it's disappointing to see the Cummins so far behind as regards torque and a factory retune is in order. That said, I'll dependability over speed but the THE number one issue their trucks have is the GVWR. Dodge is stock at 10,100 for the 3500SRW vs 11,500 for the Ford and GM while the Dodge dually is only 11,400 vs 13k of the Ford and GM. This is unacceptable to me as even if we use our site 379 to tote the backhoe my regular utility trailer plus tools will put me over.
Sorry for the ramble. To the thread starter, a 3/4 ton would be a HUGE upgrade from your half ton. Half tons are right at their weight limits when filled with passengers and that's with an empty bed. The brakes, frames and weight ratings have always made me useless to me, and I'd recommend always having "too much truck" rather than being at the limit. If you get a gas and want a smooth ride any of the 3/4tons will do, Ford's 6.2 gas is the pick. If you go diesel then make sure to get a one ton single rear wheels. Rides basically the same but you have that extra legal capacity for if you ever get a bigger trailer.