When you're working with Epoxy versus polyester, basically, the durability of epoxy beats the regular PU Polyester with the fiberglass. Epoxies are definitely a lot stronger. The surf's more stiff though, that would be the downfall of epoxies, compared to regular polyester surfboards, is that, the polyester surfboard will flex and there's more memory in the flex pattern of the polyester.
Now, the epoxy board will be a lot stronger but, will be more rigid. Epoxies are more expensive. They're roughly about $100-150 more but, like I said, they are very durable compared to the regular polyester. Most people still use the regular PU or the polyester resin and fiberglass opposed to the epoxy. The epoxies though, have been really making a big leap into the SUP's, stand up paddle boards, and stuff like that, boards that, you don't really get one every year or maybe, your long board, you want to have it for a long time, you get it laminated up with epoxy and it will last forever.