I started out using Derby blades when I converted to DE Safety Razor. I thought my technique was just off: the shave wasn't very close and I nicked my skin more often than I wanted. I was scared off by the reviews of how sharp the Feathers were. But they are very popular and customers swear by them. I took the plunge and have never looked back.If you are having issues with the Derby's, go with the Feather blades. It changed my entire shaving experience.I am happy with the blades. Very smooth shaving. My favorites so far. I have tried Wilkinson Sword( that stay sharp the longest, up to one month, but can be quite mean if in a hurry)Astra- very mild, friendly, but get dull after about a week, Darco- ubersharp, can only use them in a mild razor and only with shaving cream.I used the Derby today for the first time, without thorough skin prep, using my closest razor( Open comb Merkur), and regular soap ( vegetable oil based South of France). Result: very smooth shave,and no nicks, even after imperfect conditions as listed.Will see how long they stay sharp. My expectation is at least 2 weeks of daily, tops every other day shaving.Edit: the blade did last 2 weeks, still happy.The product arrived on time, with no issues. I would say that the blades dull relatively quick, but you should get at least a half dozen shaves out of each razor, if not more. They are ok, but I'm not sure I would buy them again. I felt like I should try them, just so I can compare between blades.i do not like these blqdes they are very dull conpqred to the reguler stainles steel derby extra blades you do not get a close shqve at all and they nick you very easy a complete waste of moner go else whereLove these blades I recently switched after over 25 years of being a Gillette person always buying the latest razor and the blades. I got tired of the high prices almost $20 for just 4 blades. These are awesome bought a high end safety razor and loving it :)These razors give a you a great smooth shave. I've tried several other razors but these are my favorite. This is an exceptional value.I bought the Derby razor blades with the Merkur Razor. My son has not had any problems with either item.Nice and smooth, will buy again...........