I expected this to be a normal lens. One wich would be VERY sharp at f/2,8 and a bit softer more open. I got it wrong: it is very sharp, even at f/2,0.
It was even sharper than I expected it could be at f/2,0.
I mainly shoot nature, although since I have this lens, I'd love to do portraits more often. That's just because this lens is a pleasure to use, expecially wide open.
Search for a cheap one secondhand, it is wonderful.