We've had our 3800 for 13 months now, and lived in it for about 4 of those, camped in it another 6 weeks total, so we are getting our money's worth. We've towed it roughly 12k miles in that time, with our 2008 F-350 SRW 4wd. It does a great job, even in the mountains, and I have no desire to upgrade to a DRW. I did add airbags to lift the rear about an inch to help with the ride, but that's it.
I think the available rear axle ratios have something to do with the tow ratings the manufacturers put on the trucks. The standard F-250 comes geared with a 3.08 now, I believe, to help with fuel mileage. The lowest F-350 is 3.55, and the lowest F-450 is 4.10. Don't hold my feet to the fire on any of those, but the axle ratios definitely affect how much strain towing puts on the power train and is reflected in the tow ratings.
BTW, don't take it anywhere with the Towmax tires. Big Headache. I replaced them with Carlyle's after a big blowout, and they have held up great.