I trusted iSmartAlarm everyday back when I lived in my SF apartment, where the locks on the building were old and the street traffic was not the best. It was super easy to setup iSmartAlarm, and the services provided were free for customers of the products. The starter kit includes a camera (with microphone and ~270 viewing availability), two contact sensors, a motion sensor and key fob. They all interact via a centralized cube that plugs into the internet. If any sensor goes off, you get a text message and push notification to your phone, as well as a phone call if you'd like from an automated service. The only downside is a lack of 911 support in case of an issue, but the notifications you receive are enough for you to take the second phone call if you need.
Sanity.io