I bought an ACO, but only because i got a great deal on it ($345 shipped if i remember correctly). I find the ACO to be functionally equal to my PROs in every way (i don't have night vision, so i don't miss the NVG settings). The non-QD mount is lighter than a QRP which is a plus, and the lack of lens covers wasn't an issue for me since i had a spare set sitting around collecting dust.

To compare the MRO to the ACO/PRO might be a bit unfair since i don't have any trigger time with the MRO yet. But, i do have it mounted on an upper and have played with it a bit. The MRO is a nice optic, and definitely fills a gap in the market, price wise. Performance wise, the dot is bright and clear even in direct sunlight, the top mounted brightness control is nice, even for a righty, as it allows for easy adjustment of the brightness with ones support hand, but only time will tell if the MRO will match Aimpoint in the durability department. Overall, in my opinion, i think the Aimpoint PRO offers a better value if you can live with the larger, heavier optic. But if the MRO hold ups well in the long run, i think it'll do well to fill the gap for someone who has ruled out optics like the PRO and absolutely has to have a micro red dot from a company with some combat heritage, but doesn't quite have the coin for a T-1 or T-2.