Is this red dot sight good or not? Any expereience with it?

If you are using it for CQB you should definitely get one. I have one cost me 40+tax, has been doing good for me for the past 5 months. it's plastic? or some kind of polymer, it got shot like 3 times and it's held up. I guess metal is fine, but I lug enough weight as is. if you are in the field, honestly don't bother. if you are playing the field save your money and get a better piston, and a 120% spring. should cost you around the same price. but if you play in an Close Quarter indoor environment go ahead. It's def. worth the money. you don't need a good one just a reliable one that is bright and you're set. My 40 Red dot sight does the same thing as my friends 350+ dollar eotech. I don't understand why anyone would pay so much for something a $40 red dot sight can do.