I have no dog in this fight, but have sold both Cougars and Open Ranges. All exterior surfaces of the Open Range are laminated. Bang on them with open hand to feel. Slide out ends and back wall. Have seen lots of 2 year old Cougars/Laredos/Sprinters/Outbacks with sagging rear exterior walls (not laminated).
Cougars use OSB roof and floor. Open range uses plywood. I would guess floor is thicker in cougar, but not sure. Warranties are different. Also, decals on the keystone products shrivel up like no other.
Having said all of that, I would own either.
Not that familiar with Sunset Trail other than seeing a fifth wheel once with a front cap slide.
