I think the XPS RIB is better at doing what it is designed to do than the GY G614 is at what it is designed to to do. That is based on no documented Rib failures on trailers verses many G614 reported failures.
Both are very similar in construction with steel ply carcasses.
The Bridgestone Duravis R250 is in this same league, with the addition of a Nylon belt in addition to the three steel belts. It weighs in at a couple pounds more than the Rib. I have used both.
I would not install a poly carcass tire on a trailer that size. Chris