I personally think the derby blades are not that bad. The work well for me but there not my favorite I like Lord Platnium blades more than Derby blades. Yet another Large case of YMMV.
I agree. They were my "go to" earlier. Since, Astras (for everyday value) and med preps have entered the picture. For some reason, the combination of Derby's and my EJ89 works the best with the EJ (maybe the reason that a Derby comes with the razor?) I don't have the quality control issues that I hear some report on this forum with Derbys. In fact, they seem less problematic than Feathers (realizing that I may be throwing the proverbial match into the can of gasoline there). Feathers just seem to be sharp for the sake of being sharp where the Med Preps appear better rounded as a "sharp" blade - just as sharp, smooth, no irritation and a couple of extra shaves.
Regardless, the three will remain in my set up, probably with Astras and Med Preps getting more use, but Derby's have their place (esp with the 89). And of course, YMMV.