One of my favorite things about this is that it looks cool as hell. It's really cheap, so its something you can buy and not really worry about it being all that important, which its not really. You only get a few times to use it in a game, and in speedball its not even going to get turned on. Its fun for target practice and stuff tho.
Not really it's fault, but since paintballs drop a lot it's hard to be really accurate on far away shots (which is the only time you would use this). It's good to help with aiming left/right, but up and down can really only be set for 1 distance since the balls drop.
Its great for the money. Only slightly useful, but it's very fun. It also makes your gun look cool. I say get it.