Pros: None for me.
Cons: Too sharp, too unpredictable, too harsh, too expensive.
Without a doubt, there is no other double edge (DE) razor blade that will polarize its users like the Feather Hi-Stainless from Japan. You either love them or hate them -- there is no middle ground whatsoever. I fall into the latter category, but certainly not from a lack of trying.
Hands down, the Feather Hi-Stainless are the sharpest DE razor blades on the planet. Too sharp, if you ask me. True, a blade needs to be sharp to cut through tough whiskers, but the skin underneath can only take so much in terms of the exfoliation that occurs when shaving. Even when using the lightest touch, I have never been able to avoid some degree of irritation when using a Feather blade.
Along with being ninja sword sharp, the Feather is also a very unforgiving and somewhat harsh blade. One should always be well-focused when scraping one's face with a piece of highly sharpened steel, but even more so with the Feather as it is very easy to draw blood from the slightest miscue -- and you most likely won't even feel it. Feathers are also a bit unpredictable with their longevity, and I have had them "go south" on me literally in mid-shave and start to scrape and scratch. Other blades will begin to pull the whiskers when they get dull, but, in my experience, instead of dulling, the Feather just turns into an ugly little shredder.
To be completely fair to this blade, my skin tends to be more toward delicate, and for those that have a little tougher epidermis, the Feather Hi-Stainless may work great for you. But then there is always the cost. The cheapest price I have seen for Feathers is about .32¢ per blade, which I know doesn't sound like a lot, but when you can get a really good quality blade like the Astra Superior for about .15¢ or .16¢ (or less when bought in bulk), then they just don't make good economic sense to me, even if they didn‘t tear me up.