PVC vs EPDM roof for 5er

I have work in the plastics industry some 40 years and have worked with pvc, epdm and tpo. and these are general terminologies. just off the top I would not go with pvc as a general statement !!! the tpo I currently use at work is great for the application (residential roof products) but remember this all above are formulated differently for every application. IE the pvc your talking about is not the same as pvc pipe. and then they do have the outdoor pvc pipe (heavy UV stabilizer's. if it was designed for the RV roof application which ever you choose it should be OK, cost does matter in plastics if your paying more it most likely has more additives in it for the application. look at warranty, care procedures and how the install shop services are. just my thoughts. one of the worst rubbers for outdoors is butadiene rubber products. so stay away from it, I doubt any rv roofing stuff would have it.