I use a Bushnell Trophy RED DOT with the four different rectules and eleven brightness settings. Almost 99% of the time I use the 3 MOA dot. At 50 yards and under the thing is deadly. The further back you get the more limited they become. First because you are looking through a 30mm tube with no magnification. Granted a 3MOA should be all practical reason shoot a 3 inch group at 100 yards, but that is if the rifle were in a vice. I can shoot about a 5 inch group most anytime, at 100 yards with mine.

Also as the light grows dimmer, the visibility through the tube becomes less. Also you need to keep adjusting the brightness setting to match the light of your surrounding area. If the brightness is to much the dot grows a tail. You then have to learn to ignore the tail.

Now remember, my experience is with the Bushnell Trophy RED DOT. I did look at a Winchester 40mm RED DOT after I had purchased the one I use. It was on sale for $69.00 . It has a bigger viewing area so you might be better off with a larger sight picture.

I personally think a good set of fiber optic sights are as good as a RED DOT, although the red dot from a solid rest can shoot some impressive groups at 60 yards and closer....