I've had 2, one for 26, one for 19. Sold off the one for the 26. The one I still have is for a Gen 3 19. Still have it. Used it pretty extensively in the past.
They will reliably function with the ammo they recommend but not other brands. One of which is Remington Golden Bullet which I have mostly run mine with. Seems to have mostly to do with the bullet shape/profile.
I have one for my 23 and really like it. It does make the overall weight of the gun lighter. I have trouble getting mine to feed reliably with a full mag, but if I down load it 2 rds runs like a champ.