Never been a fan of hanging lights on my pistol.
Having cleared many, many structures over the years in the line of duty using only tritium night sights, I am convinced that they are all that is needed and they perform admirably in that role. The task is quite similar to what a homeowner encounters while going to investigate that "noise" that just doesn't sound right in the dark, wee hours of the morning.
Lights/Lasers hanging on guns are problematic in that:
1. They depend on batteries. Batteries will make a fool of you and "die" at the worst time possible. (I hate batteries.)
2. They "mark" your position for a hostile/intruder both by the light that is directly emitted from the device and the "back-glow" that is easily seen by anyone who has allowed their scotopic vision to fully develop. Unanticipated self-illumination is bad tactics and will result in your death given the presence of an intruder who is willing to kill you simply for your possessions.
3. Operating lights/lasers requires the employment of fine motor skills to operate them and diverts/detracts from the already complicated task of operating the weapon and its controls while under stressful, frightening situations which is why we have the gun out in the first place.
4. The untrained/undisciplined typically resort to the sloppy and dangerous habit of using the light/laser to illuminate subjects/objects that pose no tactical/lethal threat or should not have a weapon pointed at them in the first place. This is usually not a problem until someone confuses an "off" switch with the trigger. (It's always fun until someone loses an eye.)
5. The untrained/undisciplined commonly begin to rely on the laser in most, if not all, lighting scenarios instead of going to their open/iron sights first. The laser should be an alternative
only when lighting conditions warrant its use. To fall into this behaviour is nothing more than pure laziness.
6. Weapon mounted lights make finding proper fitting holsters a royal pain in the behind. Modifications are usually in order unless one is fortunate enough to find a holster that is designed for the weapon mounted light.
Tritium night sights pose none of these problems since they directly replace the iron/open sights on pistols and they don't rely on batteries.
I see weapon mounted lasers/lights as mere gadgetry and gimmickry that possess limited value that can get me wounded or killed in exchange for the little that they offer. They typically become a "crutch" and interfere with good pistolcraft if the user is sloppy or undisciplined.