Secondary bonds with epoxy are far superior than polyester or vinyester. Thats not an opinion. Epoxy will bond just as well to either poly or vinyester, just lightly sand and wipe down with Acetone. A epoxy to poly is actually better than a poly to poly bond (assuming we are talking secondary bonds)
Fiberglass laminates made of epoxy resin vs, polyester resin will fatigue almost half as much over the lifetime of the boat - this is tested adn proven also. It fatigues less because it "stretches" more = higher elongation. Iso resin might be around 1.5% elongation while most general purpose epoxy is around 5%. If memory serves me correct knitted e-glass is about 4.5%.
Epoxy is easier to work with - that is an opinion shared by more everyone who has worked with both resins.
