I went with a Truglo Multi reticle red dot from Amazon on my 300 blackout, for about $80.
After installing it, (no riser needed for cowitness), I have put close to 400 rounds through the gun. I also used it last weekend on a hog hunt (day 1 in a raised blind) (day 2) through the thickest cover I've ever been in. Hanging vines, branches, palm trees, palmetto groves, huge spider webs, crawling on hands and knees, bouncing off tree trunks, tripping on vines and emerging growth. My gun and scope took a beating in there with the branches and vines catching on the sight and the gun and then when the time came, we saw the sow partially hidden by a tree. I moved to the right a bit, lined up the dot behind her ear and "pop" down she went along with another sow that was behind her. A two for one. The sight was right on, it had endured everything I gave it that weekend.
I am extremely pleased with it being that it was so inexpensive. Several guys in the group I was with was checking out the 300 Blackout and looking through the sight they commented on how clear the glass was and the dots showed no distortion. I even left the sight on overnight the first night and the next morning in the swamp buggy heading out I went to turn it on, saw that it was still on from the night before, and I was amazed that it still had the same brightness as it had the day before. I used it in bright sun, shaded areas, early morning, dark, and it was nice being able to go from red to green, vary the dot size, and go from a dot to a dot/circle pattern as the conditions warranted.
Saying that, my son is using a Vortex bought from Primary Arms and he really likes that sight.
Just my opinion based on usage. Amazon has some favorable reviews for the sight also.