Lots of good reasons here to have a laser on your handgun, so I won't rehash them all. There really isn't a downside. It is important to train without the laser as well, so your are proficient with your gun's iron sights.
I have a CT Laser guard (red) on my Khar CM9 and a Viridian C5L (LED light/green laser) on my Taurus PT145. Both work well, but the green laser is FAR more visible in bright light. If I were to buy a Laserguard today, I'd definitely pay the extra money to get a green laser.
The C5L is a great unit! IT's the smallest light/laser combo you can find (I purchased several and measured) and the only one that would stick way out past the muzzle of my PT145. I wanted something that could be used for HD duty but still be a small enough package to carry concealed. It has a lot of really cool features, too. One of those is the ability to turn it on and then holster it (in a Viridian holster or one with a magnet added) and the laser will turn off. When you draw the weapon, the laser/light with activate automatically.
I have a CT Laser guard (red) on my Khar CM9 and a Viridian C5L (LED light/green laser) on my Taurus PT145. Both work well, but the green laser is FAR more visible in bright light. If I were to buy a Laserguard today, I'd definitely pay the extra money to get a green laser.
The C5L is a great unit! IT's the smallest light/laser combo you can find (I purchased several and measured) and the only one that would stick way out past the muzzle of my PT145. I wanted something that could be used for HD duty but still be a small enough package to carry concealed. It has a lot of really cool features, too. One of those is the ability to turn it on and then holster it (in a Viridian holster or one with a magnet added) and the laser will turn off. When you draw the weapon, the laser/light with activate automatically.