Every thing about this sight is good. The red dot appears clearly and visibly in daytime and night time. The intensity levels also help you so you can use highest intensity durring the day and lower for at night. It isn't that expensive either. I got mine for thirty dollars. Also, after you install it onto your gun, it stays there. It dosen't loosen and fall off. It also lets you position it so you can point the sight upper or lower and right or left. Its pretty acurate. I shot from about 50 ft away from my target and the paintballs hit where the red dot was located. Some missed about only by inches.
Nothing is really bad about this product. I had some trouble intsalling it but it wasn't that bad. Also, you probably wont be able to find the battery at some supermarket or pharmacy. I bought them at a Radio Shack. Also, the red dot only is visible through the scope. I think this is a good thing cause other people wont see it and they wont know your about to shoot them.
This is a good sight and I reccomend it to any one interested in a sight that is good and not too expensive. Buy this sight, you'll be happy.