I have a number of Crimson Trace and Streamlight TLR-2 laser lights. (I don't know many, I have to count one day)
The CT of course is just a laser that's activated by a switch on the grip. They are excellent lasers. Saturday I bought one for my Ruger LCP.
The CT allows for very fast, very accurate low light shooting but there must be enough light to see the target.
For instance, by the time I shot the 40 yard target it was so dark the target was a Gray blur but still tight COM hits were still easy using the CT laser.
I am a big fan of the TLR-2 and have it on handguns, rifles and shotguns.
The instant you identify the target with the light you also know, because of the laser, where the bullet will hit if you shoot.
For instance,
Here's the target.
TLR-2 equipped AR. Shooting from the hip at 25 yards, using the light and laser.
Plus with the TLR-2 you have the choice of using the laser. The laser/light or just the light and aiming with the iron sights.
My thoughts are that the laser/light combo is better for HD while the crimson trace grips offer a nice advantage for carry.
Pretty much how I use them.