I think TPO is excellent. I have a slight preference for fiberglass over TPO, but only very slightly. I'd have no reservations at all with a TPO roof. And yes, I've owned rigs with both types. And also EPDM and even galvanized metal.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC