The Best Recommendation is Neither .....
.............. if you want a finish that will last for years and continue to look like wet varnish

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The best thing I've found is coating the wood (in this case teak) with System Three epoxy and then protecting it with varnish.
The attached photo shows our stern rail seats after five years in service. The teak strips have five coats of epoxy and three coats of varnish to screen out the UV. The surface still looks like wet varnish and is crystal clear. The trick here is to ensure that the woodwork is removed and hermetically sealed on all sides with epoxy and that all screws entering the wood are sealed with silicone from behind. The wood must also be completely dry, as in dried in the house for about a month.
The one catch with using epoxy is that you always have to be on the lookout for any dings in the brightwork which may allow water in. A mess if this is not soon repaired, as the epoxy ensures that any water that enters through the ding can never leave.

However, repairs are very simple and easy.
System Three puts out some excellent literature on their site:
http://www.systemthree.com/reslibrar...Epoxy_Book.pdf
Well worth looking at if you are willing to put in the extra work for a bright finish that will last for many years.