[punkwax]

Alarm companies can send police first without contacting you, but if it is a false alarm, enjoy paying false alarm fees to the city.

Some companies can dispatch guards as well. I believe that charge would be less than false alarm fees. Companies with a large guard presence like Paladin Security may have officers consistently in your area which may improve your odds of a quick response. I've also heard Provident may be able to guarantee a response time, depending on your area. I cannot confirm this is true but may be worth a call.

If you're in town, you can be first call. When you travel, advise the monitoring station and they will change protocol as you wish.

Pros would be discounted home insurance and the possibility of catching thieves in the act and keeping your valuables. The latter does not happen too often, as I'm sure you're aware.