We have ADT - have had since shortly after we moved here.
Before that we had Protection One at our last house south of Seattle.
Neighbors all around us got their houses robbed in our last neighborhood. Not us. We got stuff stolen out of our vehicles and from our driveway, but they never even touched the house.
I'm a big believer in home alarm systems. They seem to be a pretty good deterrent. Ours uses a cellular phone system to call in the alarm, so they can't even disable it by cutting the phone line. With my firearms locked up in a decent steel security cabinet, I'm quite confident that the alarm is going to be enough to keep anyone but a top notch, well prepared, determined, professional thief from getting to my guns before the cops show up - even though it isn't a real "gun safe"