I've owned pretty much every rail-mounted laser available. Everything from cheapie Chinese junk to high end green from the big brands. My GTO is a game-changer. I can't stress how incredible it is to have a rail-mounted universal laser turn on just by gripping the pistol.
It's actually a little mind-blowing when you first try it because of the touch sensing. I'm so used to a pusher switch that to turn something on just by making skin contact doesn't seem possible but it works great.
In a lot of ways this laser is like a cell phone, you didn't miss it before you had one but now you do you can't imagine not having it, it's that good, maybe even a little revolutionary.
I'll never be able to go back to a pusher switch again.
I have 1 GTO but I bought two FLXs, an FLX36 for my Beretta PX4 Storm Subcompact and an FLX37 for my Beretta PX4 Storm (see a pattern?) and swap the GTO between the 2 pistols. Works equally great on both pistols.
If I have one gripe its that when you slide off the battery cover the battery itself doesn't pop out so you have to wedge your fingertips into the battery cavity and try and pull the battery out.
It's a small grip but I think a stronger battery spring would help push the battery out so you can easily pull it out when replacing batteries. Small gripe for an otherwise excellent and game-changing laser.
Pros: Having the laser turn on by grip is the whole enchilada
Cons: Would be nice for the battery to pop out when replacing
This review was written in the old system and had content requirements that are different than reviews written today.