I done and made my choice and purchased 4 Sailun S637 tires for my Montana. I may have done the wrong thing and I guess time will tell. I'll keep you posted if I have any problems.
I bought 4 new Bridgestones "E" rated last summer. I put on about 7000 mi. going cross country and back to MA in the fall with no problem. They had a build date of no more than 6 months old. Be careful when you buy new tires, they can already be 2 yrs old or older.