ADT and SimpliSafe are opposites when it comes to home security systems.  ADT is one of the best-known names in the home security world. You'll pay a bit more for monitoring and equipment, but professionals will manage everything for you from installation to monitoring. SimpliSafe is a cheaper option, and completely DIY. You can set it up yourself, and choose to self-monitor for free, or pay for professional monitoring.  If you're looking for the ADT brand name, but also want a system you can install yourself, ADT Self Setup is a great option.