It works pretty well for us. There were quite a few bugs early on which I posted about on here. Got most of them solved except for one:
Arm the house, cancel the arm while it’s counting down. The countdown will continue although the house is disarmed. Now the only way to know it’s disarmed is by checking the telecom panel / listening for the beeping noise the texecom panel makes so if your panel is away from where you are you might have a mini heart attack the first time you cancel an arm like I did...
you can disarm and arm and part arm from C4 programming so yes you can use the upstairs sensors to disarm (why though?)
all the alarm sensors can be used in C4 programming if added to the project as well.
You could technically do something with the standalone C4 sensors and the alarm so that when motion detected and if alarm is armed do stuff but you wouldnt be able to link it back to your actual alarm without the installer doing so.
Useful programming we have:
Double tap button near the door to full arm house.
When full armed, set mocupancy to playback.
When disarmed, set mocupancy to record.
When full armed set Nests to eco.
When disarmed set Nests to normal.
Some stuff you can do with the sensors if they get added to the project would be if it’s between sunset and sunrise and the landing sensor is triggered then turn on the landing lights to dim to allow peoole to see where they are walking.
When the alarm is triggered send out push notifications, take snapshots of cameras and send them and also play a scary announcement around the house saying “u are trespassing and you are being watched”.
When house is armed turn on the nest cams around the house via the smart plugs and when disarmed turn them off (privacy ya know)