Having owned both I would go Tundra every time. Yes I own another Ram now but only because I needed a 3/4 ton truck and got a deal I couldn't pass up. My 1st Ram was a reliability nightmare, the Tundra was solid and only had 1 problem (AIP pump) which there was a tsb for and was covered by warranty. After 4 years and 100k I traded the Tundra for only $2k less than I paid for it. After 1 year with the Ram I struggled to get $26k for it (paid $42k)
Both trucks will have no problem towing that trailer but the Tundra with the 4.30 gears will do it better.