[benz]

Downsides to bronze? lets see.... it turns green! What if you don't like that green look?! What it it doesn't match your spray dodger (don't get me started on those) or your sailcovers? Shiny matches everything!
Bronze also does not mix well, electrolytically speaking, with galvanized steel. See a 'dissimilar metals chart' either online or in the Jamestown Distributors catalog. And if load-bearing moving parts are made from bronze (as in windlasses and such) they will wear out faster than stainless. But for chainplates and padeyes and bobstays and gammon irons, the only reason not to use bronze is cost. Unless you don't like green.
Ben