Vinylester resin is also a better product than polyester but still not as good as epoxy. Remember that epoxy also needs to be preped if it has cured before you relaminate on top of it. An acetone wash and a 320 grit prep is good. Remember that epoxy does not stand to the sun well and needs to be protected from it. There are some coatings (SP systems) which allow you to create a chemical bond from polyester (gelcoat for example) to epoxy laminates. You have to be careful with those but they do work. Patrick Mouligne N4601