I've tried a red dot on a number of rifles and was always unhappy. The optics are very dim and you have to adjust the brightness of the dot often. Yesterday I gave my son the dot scope and told him to look at the base of a bush about 40M away. He saw "nothing at the base of the bush and had a lot of glare." Then I gave him a 1.5-5x20 (set at 3X) and he looked again. He could easily see rocks and sticks at the base of the bushline and had a sharp image, good for early/late shooting or hunting in thick timber. 870's have a lot of recoil so I'd suggest you spend a bit more on the scope. Personally, I really like the Leupold 1-4 with the HEAVY duplex reticle. It's easy to pick it up in darker light/ thick bush AND it will survive the recoil unlike some other scopes. If you decide on another scope(unlikely) a few years down the road you can sell your Leup and get a good return on the $ as they tend to hold their value. Just my opinion but stay away from the reddots and get the scope.