I have a 2011 GMC 1/2 ton crew cab and pull a 28' holiday trailer, no complaints with power or fuel econmy but had to put in a sway bar in the back to help stabilize the truck.
I believe Four Winns are built by Genmar, which also build Larson, Glastron and Champion. I have a 2007 Larson 228LXI with a 5.7w/ Bravo-3 duel prop for sale PM me if you are intrested.