I knew this would turn into another Ford vs Chevy debate..
Since I've been shopping for the past week, here's my view. First, I'm not brand loyal - I've had a 4WD Bronco (hated it), and now a 1500 Suburban (love it). The only reason I'm moving away from the Burb is that is is way underrated for my Cigarette.
I brought a Chevy 3500 Diesel Crew Cab Diesel home last Thursday night to show the wife. I liked the interior, the Diesel is much quieter than the Ford, rode great. The thing that turned me against it was the mirrors. I backed the truck up to my trailer and I could not see the trailer or boat due to the fender flares. When I talked to the dealer he indicated that a lot of people had the same complaint and that Chevy was re-engineering the mirrors. He said they could bolt on some trailering mirrors, but I don't like the way they look.
I spoke to the mechanic that works on all my vehicles and he said to go with the Ford. He owns one (pulls a 42' race trailer with it), so he may be biased. Maintenance wise, he says the PSD is almost maintenance free, other than oil & filters. (Yes, I know they hold 4 gallons of oil.)
The Ford is rated higher in towing capacity for a ball/hitch trailer by 500 lbs. (12000 vs 12500). It "feels" like a bigger truck. I even drove the Chevy onto the Ford lot and parked them next to each other - it just looks beefier.
In short the Chevy is a nice truck - I'm not putting them down. But I think the Ford F350 PSD Crew Cab is the way I'm going.