Practical sailor had a good article on this within the last year or so. I don't recall the results other than the Bristol finish we have been using, did not do so great in their tests. They reviewed Cetol and other oils, varnishes, and 2 part varnish/acrylic. Ultimately it may just be personal taste, and how much you like to redo the finish. Some folks let the teak go gray - - like it's supposed to. (I like the high gloss style)