A couple of years ago I bought an '02 F-150. I liked it, but then the opportunity came up to retire unexpectedly, and we took it. Bought a 29' 5th wheel. When I brought it home with the Ford, I could tell it was straining a bit.
It was only 100 miles or so home with it, though, so I put that thought away.
A couple of months later, I towed a 4x6 U-Haul from MN to ID. Took the US Hwy through Jackson Hole, which involved some steep, tall passes going through the Rockies. The trailer was loaded with boxes of books and other heavy stuff I didn't want to pay the movers by the pound to move. It struggled a bit! Then on the next trip I towed a Safari van loaded with stuff the movers wouldn't take. It was full, and reasonably heavy.
Took I-90 through Montana this time. Lots of long, steep grades going over the Rockies. All this time I'm thinking to myself that this may not be a lot of fun towing that 5th wheel on the next trip!
I was in Salt Lake for a few days, so I found some trucks to look at while my wife was taking care of other things. Came home with a 2005 Dodge Ram 2500 SLT Big Horn CC, 3.73 axles, 5.7 Hemi, 5A, etc., etc. I did some work on it (tires, brakes, suspension, stereo ... you know, just the important stuff for a long trip cross-country).
A couple of months ago I went back to MN to pick up the 5th wheel. Hooked it up and tacked on a little trailer with a 13 kW generator set.
I just happened to pick a week of high winds. As in, I lost count of the number of semi rigs on their sides between Montana and Minnesota on the way out on I-90, and it was just as bad coming home on I-80! Not a good time for towing a high-profile trailer. The trailer itself was 5540 pounds, and I only had a couple hundred pounds of stuff in it. The generator trailer added another 500 pounds or so, so my total tow was within sight of the limits (7700 lbs), but it was considerably lower than the max. It's a good thing I wasn't in a hurry, but it handled the trip the way any good truck towing 6k pounds into a stiff head- and cross-wind would. Even going up and over 8500'+, I was doing 60+ mph. Cars were passing me, but I was passing 1-ton pickups with trailers, and semis too.
Okay, if you're still reading this, here's the lesson. The F-150 Supercab (5.4 V8, 3.55 rear end, towing package, etc.) had met its limits with the lighter tows I did with it. F-150 specs aren't all that different from a Dodge 1500 similarly equipped. My 2500 Crew Cab (5.7 Hemi, 3.73 rear end, towing package, etc.) never once complained, and never struggled as long as I drove it like a truck and not a hot rod.
Towing like this, the 3/4 ton likes to drink deeply from its 38-gallon tank, but it does the job much better and (in my opinion) much safer than the 1/2 ton. I was perfectly content with the F-150, until I tried towing something more than my 4x8 utility trailer on long trips.
You mileage may vary. One size does not fit all. Both trucks in this comparison were in good condition, with more than 150k miles on them.