I am a current ADT customer and trying out SimpliSafe. There are a couple of features in ADT that are awesome, but missing in SimpliSafe.
1. Announcing sensor name- In ADT, if any sensor is triggered, it announces the name of that sensor like garage door, patio door, entry door etc. In SimpliSafe it just beeps without telling which sensor was triggered. I saw a lot of other customers are requesting this feature. I don't know why SimpliSafe wouldn't add this feature.