I find that the Feathers are a BBS shave, but either cut or irritate my face. I've settled into Polsilver and believe it or not, Treet blades! Both of these blades work well in either a 34c to a R41. They seem equal in sharpness vs. smoothness!
Used a Derby today, haven't used one in quite a while. Great shave in my NEW SC, nice and smooth. Even Astra's shine in the SC.In the beginning, Feathers drew blood every use but not anymore...
I like Gillette Silver Blues blades way better than Astras.
My relationship with each of these blades.
Feather - Nicks and weepers every time, but VERY close shaves! This morning, I had one good bleeder and 4 other nicks (Merkur razor). Mostly under my nose... Best used at night when I have plenty of time to stop the bleeding. I still like the blade a lot!
Derby - Smooth shave every time. Never a cut. Not BBS every shave, but great shaves in 3 passes with touch ups. My go-to blade if I shave in the morning.
Astra and GSB - the in-between. Sharper than Derby, but less likely to cut me than Feathers. I have been nicked by them but only one or two tiny ones here and there, and not with every shave like the Feather. Can't recall a bad cut with either blade that didn't stop with a few simple cold water splashes.
I have at least 150 Gillettes, 200 Derbys, and 125 or so Astras. Feathers, I have about 15.
Good for the next 8 - 9 years I would say. I get 1-2 weeks out of a blade, shaving an average of 4 days a week.