I use that one as well. Even with a DA/SA gun, you're still not getting a true representation of trigger reset or SA pull, though, without racking the slide. I typically use it for draw/fire training (I paid the $5 to get the shot timer feature), and occasionaly just basic marksmanship and trigger press drills.Laser Dry Fire Training System by G-Sight Solutions
World Leader Laser Dry Fire Training Cartridges and Systems Supplierg-sight.com
I use that system and it works pretty well.
The downside to most of them is that in striker fired guns you have to wrack the slide each time to reset the firing pin to strike the laser.
I use a s&w 5906 da/sa pistol for mine so i just pull the trigger and away I go, but in a glock/m&p/or any other poly wonder, youre stuck pulling the slide back each time.
Now they have systems with laser guns so you dont need to mess with your gun, but they are stupid expensive. Like 400$ and up.