I can't imagine Feather blades being any sharper than they already are, Lol!!Feather blades I find a big plus too..super sharp. I`m a Kiwi located in Tokyo so are lucky to be able to buy domestic produced red Japanese packaged feathers here which seem to be sharper (in my own opinion) than the ones sold outside Japan. I reckon a 80% part of great shave is prep and lather mind you!
I've seen those red label ones available here in the states but they're very expensive. I actually thought they were the same. I'm gonna have to try them out sometime since I do like Feather blades on some of my razors.