I dont claim to be an expert on exterior finishes, but I have tested a couple that have proved thus far to do well.. one is called One Time, its an oil based product, and the second is the System Three Marine Spar varnish. I used it on 10 white oak deck chairs that are sitting outside in Vermont, it s only been 8 months on them but they look like new. The one time I put it on some old treated plywood, it still looks good . I much prefer a oil or penetrating product over a film finish, because they are easier to renew and dont peel or flake.. Just my experience and opinion, I feel sure others have other experiences.
I have also often used exterior paint untinted, it then becomes a water base clear coating , I have also used General finishes, Exterior 450 , and thus far 2 years no issue .
Now days for the home, I really like composits and vinyl …HA HA ( not really , im a wood guy)