Good addition compared to factory trigger - Apex Tactical Specialties Action Enhancement Trigger

I have installed this trigger on an existing Glock trigger guard and also purchased the trigger bar with the trigger installed. Both perform the same.
Buying just the triggers involves removing the factory trigger from the trigger bar and installing this one. It's not difficult - but you will destroy the factory trigger when removing it as you need to drive the pin holding it in place out which causes damage to the trigger itself. I used a vise and business cards (to protect the sides of the trigger) to push the pin in place. It is slightly tricky in that you need to line up the pin with the hole in the trigger bar.
After that, just move the trigger back and forth on it's hinge point before installing it in the weapon to make sure it pivots smoothly.
As long as the trigger bar is out of the weapon, you might as well polish the trigger bar. Just Google 25 cent trigger job to see how to do it.
These triggers do not physically change the trigger pull weight, however, due to the different geometry (flatter face) and overtravel stop, the trigger pull does seem smoother and lighter. I've done this on three Glocks and each one feels better.
In short, this trigger is worth it in form and function.