PU is a foam technology that is well proven and tested over decades. It has a price point that is affordable, it's easy to use, easy to fix and is the fastest technology to make (build). PU is versatile and can be glassed with either Polyester resin or Epoxy. If you are going to get a board made out of PU, consider glassing it with Epoxy resin. It costs a little bit more but is much stronger. It should be noted that PU is one of the heavier board tech's available. However, PU is reliable and it is what most of the pros use.
With EPoly, it's what you can't see that matters. EPoly construction is a traditional PE polyurethane blank glassed with Epoxy. With all the emphasis on “new technologies” in regards to surfboard cores, glassing techniques, carbon, etc., that is going on in the marketplace today we offer a simple glassing technology that provides surfers with a better product that performs at a higher level and extends the life of the surfboard for a minimal additional cost.
EPS = Expanded Poly Styrene. EPS is a different type of foam. EPS used to be hotwired out of a big block of foam. It is made out of small hard beads that expand under heat and pressure. EPS has to be glassed with Epoxy resin. PU foam can be glassed with either PE or Epoxy but Polyester will melt the EPS. Epoxy resin is far superior in strength to polyester. It used to have a bad rap because it would yellow quickly. Not the foam…the Epoxy. Since Clark Foam closed in December 2005, Epoxies have been developed specifically for the surf industry and are now whiter, stronger, and easier to use than ever.