I own more than 20 of the KRD mags from CDNN for my high powers. They do have some quirks, but I have had good service from them. They springs are incredibly strong, and almost require the use of the included mag loading tool to load the mags.
When new, they will, from time to time, fail to load the first round when the slide is closed via the slide release. Changing to a Wolff 18.5 lb. recoil spring seemed to cure the problem of the first round stopping the slide. Downloading to 16 rounds also fixes this problem.
With my mags, I always leave the range with them loaded, and they stay that way to the range session. It appears that once the strong springs "break in" they become more reliable.
I don't use for for carry, as the large plastic bumper pad increases the print of the weapon excessively.
For what they cost, and the service they give, they are good value for me.