I need a new flat roof as my torch-down roof is starting to wear significantly, and I understand there are a lot of options. The following article says, "The best alternative may be the newer single-ply membrane roof. These rubber or plastic sheet roofs last more than twenty years."
I've obtained a number of bids from roofers and they vary between using EPDM, TPO and PVC, and then there are different types of these roofs (manufacturers, thicknesses). Plus, insulation is an additional concern. What do you consider to be the best product for a flat roof that will last 20-30 years, if not forever.