I've owned an aluminum roof, an EDPM (rubber), a TPO, and now a fiberglass.
I would not sell the TPO short. It's a great product. Obviously it is more susceptible to a tear from a tree branch than is a fiberglass. It's pretty maintenance free as to the material itself. Beyond that, roof maintenance really is maintaining the seams at the walls and ends, and at all of the objects mounted on the roof. That maintenance is the same for all of the roof materials.
To me the biggest factor is the roof design. Does it have any seams that sit at some place where water collects? You'd be surprised how many poor designs there are, where there is a seam on a flat area, sealed with a strip molding, and the molding creates a dam that holds water. THAT is going to take a lot of watching to be sure the Dicor sealant over the top of it never cracks. Or it should be covered with Eternabond tape.