I like them. IMO, the biggest advantage is going from sight focused shooing to target focused shooting. You're working with a single focal plane rather than three (rear sight, front sight, target). No more focusing on the front sight and having a blurry target, instead it's eyes on target, target in focus, dot in focus and superimposed on the target (the same as with the red dot optic on my patrol rifle). Being able to keep both eyes on my target at all times is a huge advantage. This is the main reason I switched duty guns from a 1911 to a FNP-45 Tactical equipped with a Trijicon RMR02.
“Never give in. Never give in. Never, never, never, never—in nothing, great or small, large or petty—never give in, except to convictions of honour and good sense. Never yield to force. Never yield to the apparently overwhelming might of the enemy.”