We have a 2015 Cougar TT and have been pleased with it. Made a 10 day, 3,500 mile road trip as our "shakedown cruise" and had no issues with the trailer on this epic road trip. We purchased our trailer from an excellent dealer (Tacoma RV) and went through a very detailed PDI to make sure everything was in working order. Handles coming loose on the cabinets have been our only issue so far.
We are looking ahead to getting a fifth wheel in a few years and will probably go with a Grand Design or Keystone Montana. I understand that the Montana series is a heavier build than the Cougar series. Good luck with your purchase.