For many years I considered Epifanes to be the best, and still do. But the last couple of years I've been using Helmsman Spar Urethane for the finish on my "professional grade" croquet mallets. (A curious sideline that generates $300 a pop, and I have numbers 44 and 45 in process right now, since 2014.) Believe me, a varnish has to be tough to go through a season of hard play and come out looking good. As a result, I've been switching over from Epi's for everything but stuff that will live outdoors- for that Epifanes still rocks. (High solids content and superior UV protection.)
I don't care for polyurethane. Low solids content and inferior UV protection compared to quality spar varnish, plus it cures harder and is less yielding than SV which could possibly lead to crazing/cracking. SV was/is formulated for use on wooden spars (masts, booms, etc.) that constantly bend and flex even when the boat is at rest, not to mention live in environments no gunstock would ever have to endure.
Anecdote: A buddy called me this afternoon looking for help this Saturday in un-stepping the 40 foot wooden mast out of his boat in preparation for winter storage. My reply that I'll be 100 miles away deer hunting met with a chilly response. Oh well! Shouldn't have waited 'til deer season to ask a deer hunter to help with anything. Another deer hunting buddy is actually getting married this weekend. I had to ask him "What the hell were you thinking? Now your hunting seasons will be interrupted every year for the rest of your life, unless you plan on bailing on anniversaries- in which case you won't have that problem for very long!"
