Which are the most effective alarm systems for company needs?

Technology used varies a lot between different models. 

Anti-intrusion alarms use more or less sophisticated sensors. You can also configure them so that alarms installed in a sensitive area are triggered more quickly. To avoid jamming, it is preferable to choose a wired alarm equipped with an anti-sabotage device.

For improved security, it may be more interesting to subscribe to a remote monitoring contract with a service provider: not only will they be better able to guide you in your choice, but their intervention can be more effective than the simple sounding of an alarm.