I will continue to use polyester and ply, it works well for me.
I have just been looking at a book by "Dynamite Payson", he talks about cheap ply and polyester boats lasting a long time.
If you are investing loads of money and time in making a large boat then you may well want to use the best available materials.
If you are trying to learn about boat design and construction through practice, then there is a lot to be said for using other materials that are no so precious.
I fully understand the merits of both materials and have used both on a number of boats. I would rather be on the river than saving up for epoxy.
The years may well tell on the boats that I have built so far, but I need some natural wastage because all she says at the moment is "not another boat where are you going to keep that?"
It also lets you have a Viking theme bonfire party "valhalla", then you will see how well ply and resin will burn. I burnt an 8 foot ply epoxy pram once and was very supprised.
Boats can be built from lots of things, 40 years ago when I was helping my father build dinghies there was no epoxy and very little polyester in use. I think we can all worry too much about the materials that are being talked about today. Perhaps we should go back to using birch bark or animal skins and tar, far more eco friendly far smaller carbon footprint.
I think that the most important bit is "just do it" as Mr Nike would say.
H-A