All three would tow your rig very comfortably. I like the looks and interior of the Ford and Dodge over the GM's. I haven't really seen the 2015 GM though but I hear it's really nice. I test drove a 2013 Dodge MC dully with the Aisin tranny in the Laramie trim last week and wow what a truck. I'm comparing it to my 07 Dodge MC which I love but night and day difference. The sticker on that truck was $64K which is crazy but all three will be around that price. To me the Cummins/Aisin is the best on the market today but I would test drive all three and go from there. $5000 off MSRP is too high priced. You can do better then that.