Installation was free - $41.99/month for 3 years.I started off with APEX and they changed to APEX/ADT. I have been satisfied with the service. My only complaint was that I had to have a service teck come to my home to fix something, and unfortunately because the company had changed hands, I had to pay for the service call. That was $35.00 that would have been free to me if they had remained APEX.
We have had no problems with the alarm system. They are on top of things. A friend who was staying at my house wanted to check that the batteries in the smoke detector. They did not realize that this was the smoke detector that was attached to the alarm system. The good news is that the alarm company noticed that the detector had been "touched" and called to inquire. All in all, so far so good. I believe that I will continue to use them when my contract runs out this year.