I have to say, it seems that the top 3 blades for me are all manufactured in the same plant. Super Iridium, Astra SP and Gillette yellow are all made in St. Petersburg Russia. Yes, I think all these are better than Feather.
It makes me think 2 things.
1) Whatever they're doing there I hope they don't change it, they are setting the standard for blade quality in my opinion
2) Gillette, even though hated by many on here, really seems to be "king" at quality blade production. I have to give them credit, I'm not sure anyone does it better.
Now, I obviously haven't tried every blade on the planet, but I've tried many, and there is clearly a noticeable difference from blades produced at this plant. They are head and shoulders above the rest in terms of quality of blade and consistency of that quality from blade to blade.