I like the Holosun 507 K, and I have a few other brands. On my carry gun, a S&W Shield Plus, I have a Crimson Trace. It’s a good sight, but it was bought as a package deal and was already on the gun when I bought it. On my M&P 10mm, I have the Holosun and I prefer it, not only for the reticle choices, but it also has a tiny solar panel on top that supposedly will work even if your battery fails. I didn’t buy it for that, but rather the reticle choices and the good reviews. It might be a little large for a carry gun, but in my opinion, just right for a duty, range, or match gun.