I have the Crimson Trace grip mounted lasers.
I don't like a weapon mounted light because you have to point your barrel at whatever you want to see. I carry a Streamlight Strion led (160 lumens, 3 light levels and strobe, with rechargeable battery) every day. What would you feel like if you were clearing your house when your wife heard a noise and you brought your weapon mounted light around a corner to see the darkened hallway and you lit up your toddler. To me that is not worth having the light on the weapon. Also I have read that the light is what someone would aim at if there was someone firing at you and you can hold a flashlight at arms length.
Just my 2 cents.