I really enjoy shark SS blades and am currently shaving through some GSBs that I can't stand. Worst EVER was the dollar store Indian personnas: I shaved, I cried, and there was no clear winner.
You'll get differing opinions here but for me the worst blade I ever put to my face were Gillette Super Thins. Dragged all over my face, and I swapped it out for Derby! PIF-ed them to a shaving newbie mate of mine.
As you can tell, my opinion of Derby is probably way different from yours.