Water Temple. If you knew me, you'd know that I'm a HUGE Zelda fan.
Plus the Water temple in Skyward Sword had the best water temple, even though we aren't talking about that one... but to be fair Rainbow Road also has many versions of itself.
Rainbow Road is awesome since there are so many versions of it and they all look cooler with each one. The water temple looks nice but seeing as I haven't played LoZ at all along with the fact that it looks rather dull, my pick goes towards Rainbow Road (or Bridge according to Manly).
Rainbow road. It looks pretty, but under that candy coloured exterior beats the stone heart of a murderer. I'm sure it's made from the tears of children, or something.
water temple... idk about you... but i dont want to be in a place where my only options walking in circles on a rainbow (that would make my eyes hurt) or falling into deep infinite space...
It's not really a fair vote from me, considering I'll always vote for the Mario option over the Zelda option since I've always liked the games much more, but because I do prefer all things Mario to all things Legend of Zelda, Rainbow Bridge/Road gets my vote!