I started with a 2005 F250 with the 6.0 PSD. It started hauling a 11k+ lb toy hauler and finished hauling a 4k lb truck camper while towing an 8k lb enclosed trailer. It did both jobs well for my ten years of ownership but was replaced with a 2015 Ram 5500 6.7 CTD in anticipation of a larger camper and trailer in future years.
The Ram has less than 8k miles and is handling this "light" load easily even with travel through the Rockies of UT and CO.
If you don't tow, I strongly would consider the gasoline engines for your next truck to gain payload. If you tow and haul a camper at the same time, get a diesel. Both the F550 and 5500 were strong trucks. Ford beat out Ram in features and specifications, but the Ram was more value for my money than the Ford in the end.
