I have only tried 3 blades so far (Wilkinson Sword, Astra, and Derby). The Astra's were the worst for me. I got bad razor burn each time I used them.
Of the approximately 60 blades I have tried, Merkurs are the only ones that were really bad in every razor in which they were used.
Another case of YMMV. I always get excellent shaves with the Merkur blades, especially in either of my 2 Merkur razors. The truly annoying, short-lived blades that provided uncomfortable shaves were given by a 5-pack of Dorcos given to me a while ago.
I'm not sure I have a worst blade. Each blade is different and reacts accordingly with razor, length of whiskers, prep and my technique.
Practice makes quite a difference when it comes to blades...but I still hate Merkurs while their safety razors work so well. Go figure.
Gillette Stainless, red pack, for sure. I really don't know why they make them. Platinums (DP) are much better for same price.
Believe it or not I think the first 2 shaves with feather blades give me more irritation than even my cheapest blades, even in my mildest razors. But they work great shaves 3-4. Those things are sharp and don't pull at all, I was surprised they irritate.
They irritate because they are so sharp - they're peeling off extra layers of skin, thus causing the irritation.
I'll never use another Feather blade again. I nearly slit my throat with one a couple of years ago, not to mention the cuts I had on my cheeks and chin.
No matter the razor I have never liked Derbys. A Merkur came with the Mergress and although not impressed, it was the first three shaves with the razor and the only time I tried it.