I'll tell you mine on Derby. In the past (about a decade ago when I started this beautiful journey) there was lot less choice as there is today in terms of instruments (both hardware and software). The Edwin Jagger DE89 (or the Muhle R89) was one of the "obliged" first step into a getting a "first decent razor" (the Wilky Classic is a decent razor alike, but it was generally accepted as no more than a starting razor due to be mild and cheap). At the time, the DE89 was issued with Derby blades (the green pack). Today, I believe it is issued with Feather blades (which for me are the best match for that razor), but I may be wrong. This generated the view amongst many newbies that these blades were somewhat dull and ineffective. For some, this is true (as a matter of fact, YMMV). For some others, it's not, but regardless of the Derby itself, when you begin, you inevitable lack the skills necessary to handle the razor properly, as well as your skin has not adjusted to a more effective way of shaving yourself (again, this is my personal opinion). I've too considered these blades to be crap for long time. I gave them another try last year in the same EJ which I still own. I got a good, smooth and irritation-free shave. The green derby in particular, are probably amongst the smoothest blades around given the number of treatment they receive (PTFE, platinum etc). Yes, they are not super sharp. With my EJ I can get one good shave and, at best, a mediocre 2nd. But where these blades excel for me is in more aggressive razors. With my Fatip OC, I can get 4 good shaves which, considering the price per blade, is a pretty good result for me. Sorry for the lengthy post.