Another plus for the EPDM or vinyl roof is sealing it. Metal roofs tend to expand/contract in the sun much more than EPDM or vinyl. This flexes the sealer at all joints causing them to leak sooner. My experience has had the sealer hold better on the flexible membrane better than on metal.
2003 Dodge HO 6 speed Laramie Dually, Jordan controller, RDS fuel tank, Air Ride 25K hitch
Carriage 36' fiver, Onan 6500, Prosine 2K inverter, 3 slides, MORyde IS and Kingpin