I did a lot of research before deciding on a home security system. I looked into Xfinity Home, ADT, and a few other smaller outfits. I went with the Link system through Costco because it offered a great deal for the price. Link is basically an Alarm.com dealer, a cellular-based alarm and home automation system, completely wireless (except for the control panel, which needs to be plugged in). No wired sensors or professional installation necessary! The system itself cost about $200, including the motion sensor, 3 sensors, wireless thermostat, 3 door/window sensors, smoke/heat detector, and 2 lighting modules, and is practically infinitely expandable. If you don't mind self-installation, it's a truly excellent system. Every component can be monitored through smartphone, tablet, or computer. My favorite part is the thermostat, which is every bit as good as the Nest thermostat, if not better. Maybe not as slick (not designed by Apple), but has all the functionality at a fraction of the price. It can be automated based on your (phone's) location, and can be controlled remotely. I had one false alarm, which was my fault. But I was called and texted promptly when it happened, so now I know the system works. In short, I'm very happy so far.