Any filler will work. I never tried the evercoat stuff, always used the cheap bondo, one time sprung for the "bondo gold" but didn't like it. I preferred the original bondo so I could judge by the color about the mixture.

You can mix in fiberglass resin into any of the hardened body fillers, to make it runnier/smoother (called a skim coat)-- that works really well for filling in scratches, nicks in paint, and over a layer of (already hardened) filler mix to fill in pinholes and sanding scratches. With fiberglass resin, it takes a bit longer to dry.