I went with the Grady scuppers, they aren't cheap but still look new. The Gemlux's are OK, and it's too soon to tell with the Perko's. I went Bronze for any fitting that's by the water line. It's not a big deal on a boat with bottom paint but on a clean hull they'll be ugly. They will not show rust stain or erode, but they're ugly.
The 316 SS can be a lengthy disuccion, but Stainless is not stainfree.