We just got back from our first long trip with the Andersen Ultimate 5th Wheel Hitch (non aluminum, rail mount) and first mountain trip with the F250 6.7.
We had not been out of Florida with the hitch since we got it in May. After a 1,542 mile round trip to the Smoky Mountains, I have nothing but good to say about the hitch. Quite, smooth and no chucking or bucking. It performed as advertised and was a pleasant experience, two thumbs up!
As noted by many posters before, I can add a great review on the F250 w/6.7 and exhaust brake. Biggest grade was 7% with a few 6 1/2 thrown in and between the tow/haul and the exhaust brake I don't remember having to touch the pedal going downhill at all! I realize I didn't exactly cross the Rockies but I would not hesitate to take that trip either. The combo worked great and I just thought I would give an honest evaluation of our experience. Happy camping, be safe!