I've had several different systems over the years. ADT ( formerly Brinks) is the latest...
Loved it...
In once house we had not only the doors and windows alarmed.. but we had the master bedroom door too.. ( dont remember why, but I know it was a special feature... seems it was something about if they break in they would kit the master bedroom for jewelry, etc and be gone before police arrived..... the alarm was silent)
I know it saved us a few times...