kinda hard to use in broad daylight
brightness switch changes dot color rather than brightness
I exclusively play 1-on-1 to 3-on-3 desertball (like woodsball, only more sand and less trees) with my friends. Our style of play is to be as stealthy as possible, so we're almost always crawling around and sniping, though we do also get into all-out firefights. Since it's generally a "you see him before he sees you" environment, the sight definitely helps line up my first couple of shots before I have to move. Being able to keep both eyes open while using the sight is a big plus, and it doesn't matter what angle you're looking through it as long as you can see the dot. It's there when you need it, but doesn't get in the way when you're aiming via the "tracer method." My only complaint is that the dot could be a bit brighter. It has a two-position switch which is supposed to adjust brightness according to the manual, but it actually just changes the dot color to red or green! I keep it on red since my opponents are almost always in or near vegetation.
I definitely like it. When you have the extra bit of time to take aim, it drastically improves the shot. The accuracy of your barrel is the only limiting factor.