I can’t speak on the smaller ones, I’ve got the 3.5 and love it though. I bought mine with 50k already on it.
Yeah I took a 3.5 for a week and it pulled my 8000 lb camper almost as good as my old 6.7 powerstroke. The 5.0 struggled with the 8000 lb camper but it did put it. Now my camper is only around 4800 so the little 5.0 pulls it just fine.