I've been to Bert's a few times--the hamburgers are very good, as are their home-made chips. Another particular highlight: the local Pine Island clams. Oh so yummy!!
One drawback -- it frequently becomes busy in the restaurant side, usually leaving the waiters a bit short-staffed. Be sure to relax and go with the flow!
But the truly great thing about Bert's is that you can pull your boat right up to the dock for a nice bite to eat!