Rams seem to have the lowest payload. The F150s with the aluminum body can get pretty high numbers.Payload is often what is used up in a half ton truck. My F150 has 1940 lbs of payload based on the door jamb sticker. This sounds like a lot until you put 4 people and some other stuff in the truck. This woukd kick your allowable hitch weights down to a 1000 lbs or less. There are a lot of half tons with a lot less payload then mine.
But I'll still stick with Ram.