I have purchased several of them (1911, Marlin rifle, Walther PPK/S Ruger, etc.), and I find them to be excellent. Now, I do want to warn you of one small issue. I am a very anal, detailed person, so I would not rate them a 10, but probably a 7 or 8 out of 10. On the Walther PPK and PPK/S video, gunsmith Robert Dunlop (his surname might actually be Dunlap) does an excellent job--except for one small problem. When he disassembles the PPK/S firearm, it shows that the cartridge indicator pin has actually been installed backwards. I'm guessing that one of his students probably did this, and he did not know that it had been installed incorrectly. That will cause several problems. To his credit, he does install it the correct way (the "bulb" end forward toward the muzzle, the spring tail toward the top of the pistol slide). One last thing. I'm talking about the "new" style pin not the "older" version.
I initially installed mine backwards, and it caused multiple failures to feed. I don't have time to go into the analysis right now, but it allows too much of the cartridge indicator pin to enter the chamber area of the firearm. That is why the "bulb" is there to prevent that. Other than that, I find them excellent. Hope this helps you.