I can't say how this particular Safariland model works with an actual Glock (though I can vouch for other products in the ALS line), because I only use this model with a training gun. However, it performs well in training, as expected. The ALS system is perfect for those of use who believe the trigger finger only has one job (and that job is not releasing the gun from the holster to draw it).
The downside is you don't get as many carry adjustment options for the money as with some others nor the possibility to carry in as wide of a variety of rigs.
Pros: Retention System
Cons: Feature set not as flexible or adjustable as the competition
This review was written in the old system and had content requirements that are different than reviews written today.