Man in the training in the self defense school will argue about the use of lasers on firearms.    Lasers are used for as many diverse reasons as any tool.   You can use a laser to direct someone to a target, highlight a threat, targetting a threat and using the laser dot to give you an approximate point of impact.   When lasers first came out, there was evidence that operators were using them to aim and for close quarters fighting, sometimes aiming is not necessary and will slow you down in getting the first hits in.   Hits count and the first hits usually go to the winner.
Whenever you think about putting a laser on your firearm, think about the tactics and reasons for using them.   The Crimson Trace laser grips have an excellent reputation for durability and will fit for most modern handguns.    Lasers won’t slow you down if you don’t let them, they can actually help you in many ways and there are some instruction DVDs out there that will show you how.    Lasers are also a good weapon of intimidation and can give some comfort to less trained shooters.   Whether your carrying a laser for your Glock, 1911, Sig Sauer, XD or revolver, remember, it’s what’s in your head that helps you win a fight.