Alarm systems with multiple good loud sirens are the best. Being in this business, I have access to free monitoring that I did not even take advantage of this for years. I finally used it, just for FIRE. Police response is questionable, and besides they could care less about your property losses. Some buildings I don't even lock, just set the alarm. No one should be going in there anyway, and why have the added damage? Yes, it's true, I always hear, "they will get in if they want to". And the alarms will go off (making them deaf) when they do.
But just to be clear. Alarm companies make their money (as I do) on recurring monitoring revenue. Sirens cost time and money to install, and can lead a customer to question why they are paying for monitoring at all?
I once installed a local-only system in a farm house being rennovated. It had four external 30 watt sirens. The night after the appliances were delivered, the place got broken into. Nothing got taken and there were two skid marks in the driveway where someone had obviously left in a hurry. That was a good feeling!