SimpliSafe is OK if you want bare bones fast DIY. To use an AR-15 analogy like above;
If SimpliSafe was an AR, it would have a 20" barrel, 1/9 twist, full stock, carry handle,
and you are stuck with that configuration (assumption being the components
are fixed and not swap-able). Still a good rifle, still can be used for defense, hunting, target, etc, just no flexibility.
Example;
Simplisafe, wireless only, proprietary components, proprietary monitoring, one motion detector available, one entry sensor available, indoor sensors only, etc . . . .
Vs;
Honeywell, wired, wireless, or both wired/wireless components at the same time for best configuration, non-proprietary components (Bosch motion sensor no problem, Tane alarm contacts no problem), motion detectors - dozens available (indoor/outdoor, dual tech detection, short range, long range, different size pets, tamper proof, on and on), alarm contacts dozens available, (inside mount/outside mount, recessed, hidden, long range, wired, wireless, on and on), expandable power supply, self monitoring, professional monitoring similar to an unlocked phone/you can shop "carriers" for alarm monitoring or do your own free monitoring via your Smartphone.
The Vista 20P is dual partition (2 alarm systems in one), right now my alarm in the house is off/alarm in the detached shop is on. Good example, the spare bedroom with your safe, or reloading room in the basement, always on and protected from bad guys, snooping kids, etc.
SimpliSafe OK for fast and easy. A real alarm is better for those who want flexibility and do not mind tinkering/setting up their system.
Examples of Honeywell contacts, just some of the available options shown here
Motion detector overkill but example of tri tech detector
Honeywell advanced detector
Lots of motion detectors Attached File