To me, Kai blades are perfect for using in a Gillette Tech, which is my daily driver. The blades are just a tiny bit wider than normal, increasing the agressiveness of the Tech just a tiny bit, and because of their more blunt sharpening angle they are long-lasting--I get up to 14 shaves from one blades, which for me is 28 days as I shave only every other day. Normal blades work fine in a Tech as well--I've tried at least a dozen. But I like the mildness of the Kai blades, and their durability makes my morning shaves very cheap, which was one of my goals when I got into double-edge razor. I just got tired of paying for expensive multi-blade cartridges that I like less and that irritate my skin. Even in older age I still have a light, silky beard, and sensitive, soft skin, so your mileage may vary as they say. I am perfectly satisfied with the closeness of the shaves; I do with-the-grain (WTG on shaving forums) and against-the-grain (ATG) only. And I use shaving oil, not shaving creams or soaps. But I'm never looking for the perfect baby-butt-smooth (BBS) shave. I figure, why bother? It grows out again soon anyway, Still, the shaves I get with the Kai are very smooth at first, and that was the first thing that attracted me to them. Most importantly perhaps, the mildness of the razor and blade mean I don't have to be particularly careful in order not to nick or cut myself. I get a "weeper" very occasionally, usually when I am in too much of a hurry, but the razor/blade doesn't bite me unexpectedly like medium-aggression and aggressive razors do.