The chief reason against polyester is it's lack of flexability. I was once working with polyester resin and a spilled puddle on my work table which hardened. Next day I peeled it off and it dropped on the floor. It shattered into pieces. Epoxy will never do that. or will a puddle of carpenters glue. They have aditives for flexability however it doesn't do well as a glue since it will shatter or tear off at wood fibers. this is why polyester is used to make great fiberglass layups / not for use in sticking to anything.