Grand Design has, until recently, put Westlakes on all their RVs. Earlier on, there were issues with the Westlake LR E tires. Since GD started putting the Westlake load range Gs on the Solitudes and Momentums, there have not been any documented issues on either of the Grand Design forums (and folks do like to complain about tires). Our new 2020 Solitude came with the load range G Westlakes (we had Sailun Gs on our previous fifth wheel) and I plan to run the Westlakes for now. I may replace them a bit earlier than I would have the Sailuns, but the Westlake Gs are developing a good reputation among those who have them. When replacement time comes, though, it will be with Sailun S637s.
Edit/PS: no matter what tire you run, I consider a good TPMS to be critical.
Rob