I have never used sherwin williams epoxy, i applied Rust-Oleum like 6 years ago to my rental hose garage and still looks like new. I would use Rust-Oleum but make sure you buy the professional coating from amazon or somwhere else, and might be a good idea to apply the clear coat on top too. I didnt do it and my epoxy looks good, but not shiny.dont get the one you can get at home depot; its water based and might peel off, happened to my friend and heard from different people too. Also pretty soon i will apply Rust-Oleum professional epoxy to my current 3 car garage if you need pics i will post some once I apply it and if any if u have questions let me know.,