Never used a laser on a handgun, due to the fact I consider it to be defensive by nature. Never seen a practical use of a laser, again due to the close range a handgun would be utilized for. I've used IR lasers on everything from an M2 to an M4 due to the use of night vision. Not to mention the fact it does illuminate a target in the dead of night.
There's been a billion debates about lights, but in my own experience, they work. Not only for target acquisition, but it is also that saving grace keeping you from making a judgement error. At times, it is an element of surprise if using the right light, but rarely would you be in a offensive position, especially with a handgun. I have a Surefire on my bedside Glock, a Surefire on my AR, and a Surefire on my 870. I'm a fan of A product that always worked and saved lives.