I know the sharpest. At least the board consensus appears to be Feather, sometimes Kai, but I was curious whether members place smoothness over sharpness.
Of all the samples I tried, by far the smoothest is the one I've stuck with, Astra SP. It was the only blade that hasn't tugged me even once, and I'm nine shaves into a blade which is as smooth as the first. I wasn't getting more than four from others.
I love the Shark Super Chromes. They have been the smoothest and longest-lasting blade I have found so far. GSBs run a close second. The funny thing is, I find the Shark SS to be just mediocre.