We have a 10 year old wired system installed by a local quality security company. Then they were bought out. Response call center in another state (they are clueless about local geography), billing problems, you name it. General PITA. Other security companies won't work with another installer's system.
Today we would install a wireless system that called us first as we set it when we are away.
Most burglars avoid homes with a horn that goes off upon intrusion. Secure locks on doors and windows that are USED help a lot. The one time someone got into our home they entered through an unlocked sliding door at the back. The horn went off, police came out but couldn't find anything amiss. The perp had hidden in a garage storage area behind boxes. Once the cops left he opened the garage door and fled. Now we check all the doors, even the ones we think are locked. We lock the door to the garage storage area and turn off the power to the garage doors.
One homeowner in the region managed to kill an intruder, but I think most thieves prefer to work empty homes. If they find a gun in the home they will steal it and sell to a bad guy.