You can't go wrong - Holosun ARO MRS Advanced Rifle Optic 1x22mm Reflex Red Dot Sight

This is the second of these that I have purchased. I paired this one with a holosun 3x magnifier. I was concerned that using the circle with the dot under magnification would obstruct the fov but it's not an issue. The reticle is sharp and the range of brightness makes this useable in any lighting condition. The circle dot is great for getting you on target quickly, and the dot is the perfect size. Large enough to clearly see but small enough to offer pinpoint accuracy even under magnification. The glass is very good. I don't notice any distortion. The mount is bombproof. Holds zero on 9mm, 5.56 and .308. I have an astigmatism but when I wear glasses and turn the brightness down to an appropriate level for the lighting conditions I don't have any issues. I've tried a bunch of red & green dots and this is one of the better ones for my condition. You can spend a lot more and get fancy but this gets the job done just fine. The price is right and you are getting Holosun quality and durability.