I have tested about every finish I have heard of by finishing a block of wood and putting on the roof of my shop for a year or more and in all cases left it there indefinatly and checked it form time to time...
My best results were with Flecto Varathane for waterproof, but it has Trulene and thats is bad stufff I'm told..
All things considered, I like Gun-Sav-or from Brownells the best. It is easy and fast to apply, it lasts well, easy to apply, comes in gloss or an eggshell low luster, it is as waterproof as about any finish, easily repaired, and matches well with itself on repair, it has all the needed elements for a good finish.....
Remember a high gloss layered finish is the most waterproof but its also very bright and glossy, and I prefer the low luster and less waterproof finish, its a trade off at any rate, but as long as they make wax, I can get by that.
Some folks can apply one finish better than another and some folks can apply a finish better than others can apply the same finish..The secret is to find a finish that suits you and that you can apply and stick with it...My problem is I am always searching for a better finish and the end results are always the same, some I like better than others and thats as far as I get.