Skeena is 7 years from launch and is holding up very well. I coated the entire top, including the comings with 4 oz cloth. It's super easy to work with and I would definately do it again. And of course it strengthens the joints.
I also added glass to the seat tops. Impacts from the sprits and general banging of my paddleboard paddle, dropped coffee cups, and other dumb stuff has confirmed the decision. I don't think it addds much weight.
I backed into a mailbox by accident while the boat was on the trailer, which would have surely broke into the plywood of an un-glassed cabin. The glass helped spread the impact and while it got a good scuff and needs a touch up, away I went on my trip last fall when it happened.