Hello Brian, I am new to this forum but will give you my $.0002 cents and hope it helps. I have a glock model 30 that has been my carry for the last two years. It has the MMC nite sites and I could not be happier. The sites are functional, asthetic, very easy to adjust all around they could be described as bomb-proof. Site acqusiton is fast and precise, they really seem to fit the model 30. My model 30 has truly been tested and when I replace the Trijicons on the Model 21 it will be with the MMC's. I will admit that the MMC's are not as bright as the trijicon's or my Wilson Combat nite sites, but I hear that MMC has resolved that issue. However; something can be said for not having extremely bright sites, the higher visibility of the Trijicons could be perceived as site picture for someone else in the middle of the nite. After reading the previous post I will agree on the previous post concerning the Heinie's. The Heinie's do work well on my Colt, but the MMC's do seem to conceal easier for me on the Glock 30. I hope this helps and good luck on you choice. Greysky