I have the Crimson Trace LG-645 on my HK 45c and love it. As one of the guys said, it's not something you take on and off. I had Raven Concealment mold me a Phantom holster for it. I prefer the grip activation laser instead of the "push a button first" type of laser, as I have smaller hands and short fingers, and it takes me too long to push the button and then obtain a grip on the pistol. (Maybe I'm too uncoordinated also!!)
I do wish it also had a light, so I carry a Surefire light with me also. Some folks don't like lasers, and to each his own. I have the night sights on mine, but I'm in the 60ish year old group and it really helps me acquire a sight picture faster than without. I do fine with my shooting glasses on at the range, where I can see my sights clearly. However, without the glasses, I can't see them distinctly enough to shoot as accurately. At night, at home, I can't worry about having shooting glasses next to me all the time, so the laser works for me. However, if you don't like lasers, God bless you anyway. We're still allowed to use whatever floats our boats individually. As for me and my old eyes, though, I like the Crimson Trace.