I agree, very subjective question. I've ran both the Aimpoint Comp M4 and the PRO on my XCR-L. I've kept the PRO. Great optic out of the box, comes with lens caps (rear clear for expedient use,) mounting base and a 3 year battery life. It's always ready if you need it. The rubber cover for the M2 and M3 fit it too. Can be found for under $400 quite often online.