I haven't used the Dicor product but have some experience with EPDM roofing. The real truth is that unless you park in Southern Arizona 365, a protectant isn't needed. Most EPDM I see doesn't fail from UV degradation but from age. I do live in the Northern tier of States.
There is a case to be made for coating with a white coating as that helps to keep inside temps down and it does make the roof look good. Knowing what I do about Dicor, I would assume their product is good but couldn't say how it compares to others for economy.
