I am with everyone else about the superiority of Dorco Prime Platinum blades, these along with Silver Stars, are my daily drivers. I haven't found a razor they don't work well with, but they go particularly well with my collection of Fatips.
I am like several others, a couple of years ago I bought a 1k brick off the bay, so I won't be buying more in this life. I am unsure if mine are Korean or Vietnamese, but it seems to matter little. This is a fine daily driver blade.
Dorco is a South Korean company, but Dorco Prime Platinum STP301 blades I purchased were made in Vietnam. I understand that the Vietnam plant is a state-of-the-art facility. The quality of the blades I received were top notch.
I have a very tough beard and sensitive skin. I like my blades very sharp and very smooth. The Dorco Prime Platinum blades excell on both counts. Their low price when purchased in bulk makes them a superb value.
If you purchase them, be sure to get the Prime STP301 blades. There are similarly named Dorco ST300 and ST301 blades that are not the same blade.
I had my first go with these (stp301) and boy did they not agree with my face. Tried with and r41 and 89 head, resulting in two of my worst shaves in quite some time. I'm somewhat surprised as they sounded like they would be just up my alley.
I was shopping around for Astra SP blades a while back, but read too many contradictory reviews about the "new" branded blades and possible counterfeits, so I went with the STP301. Do not regret. For me, they perform as well and are cheaper.