I have moved away from smartthings embedded automation Smart Home Monitor, and am happy with the results.
First I use ActionTiles as my human interface. Actiontiles only works with the SHM instance that is accessed via the classic app. I am not using the classic app for anything else and I do not want to have to access any app to simply acknowledge and dismiss an alarm state anyway.
Second SHM is pretty inflexible in that it does not allow pairing of motion sensors to creat a very reliable intruder detection. Anybody that uses motion sensors knows that false alerts happen based on sun etc… Pairing two sensors together solves this problem.
Third is that SHM does not allow the use of presence sensing to arm or disarm the SHM intruder alerts.
The actual implementation was easy peasy. I just wrote automations in the smartthings app to perform the functions I want.
In Actontiles I have a button that toggles the mode between home and away modes. I do not use night mode, but of course could. I also have a automation that changes the mode to home when any of the arrival sensors are detected. That way you do not need to disarm the security when you get home.
There is an automation to turn all sirens on, and send notifications if the mode is away and both sensors in a particular area detect movement.
Another automation to turn on the sirens if a fire/co detector alerts
And another to turn on a single siren if a water leak is detected.
Another automation is triggered by a actiontiles button to silence the sirens.
So far I am VERY happy replacing SHM, as I ave gained back flexibility in my alarm system and made it compatible with ActionTiles.