...I will say that with Feather brand blades, I've never had a closer shave.
Agreed! I learned to shave 50 years ago

eek

with a Gillette safety razor but eventually "graduated" to the double-edge Atra II and similar "land-fill specials." But a few years ago my regular razor finally died and I went to find a replacement. Double-edge razor, you say? Whazzat? No, sir, you need a THREE-blade razor! The stuff I was looking at looked more like candy than a razor.
Long story short, since Gillette stopped making safety razors in the mid-80s, I went online and ended up getting a Merkur safety razor, a decent badger-hair brush and Feather blades on the advice of the website I was on. (Classic Shaving in CA, I think.) Haven't looked back since.
Can't remember what soap I was originally using but they stopped making it and I settled on Kiss My Face, which, despite its "metrosexual" name, is really good and not expensive. Unfortunately, the company is under new management and the product is not currently readily available. In the meantime I got some Proraso. They've been making this since about 1907 so they know their stuff.
And Feather? I recall looking them up, as I figured they couldn't make ends meet just making old-fashioned razor blades. Nope- I think their main line is surgical scalpel blades, so they know about sharp.
There's quite a brisk market in double-edge razors, as well as open (cut-throat) razors and all the accoutrements. And I see lots of old Gillettes in second-hand stores. They were made to last. I think King Gillette sold them as almost a loss leader, but made his fortune on the blades.
The idea of needing a three- or even four-edge blade is a load of horsepuckey, IMHO.