Depends on who you talk to about an alarm system. Every person has a different need. Not all people are about overselling and making some bucks.
I have the Snuffdog and Smokey alarm system. Works great, especially the Smokey part. He barks whenever anyone comes into the county. BTW, he's available for a small adoption fee. the JCAPL has plenty more, too.
Harley did my sisters alarm system, she and her hubby are very satisfied If I needed one, that's who I'd call - but I have a dog named Percy who is a 24 hour a day sentry and if someone breaks in, no cops are necessary, the coroners' vehicle will be sufficient.
I have 2 very protective big dogs, but a baseball bat or a gun would take care of them real quick. Harley's ADT service makes me feel SAFE.