Holosun has a very good reputation, and I know of a lot of trainers that recommend them as the best closed emitter handgun optic. My two main defensive-type carbines are both set up with Aimpoints, a Comp M5 on one and a PRO on the other (both with Scalarworks mounts).
“I'd rather have questions that cannot be answered than answers that can't be questioned.” —Richard Feynman