I’ve been using AlarmRelay for several years and IMO they do an excellent job monitoring my ELK M1 system.  It was very easy to set up.  A technician called me and walked me through configuring my M1XEP to communicate with AlarmRelay.  I took probably less than 5 minutes.  AlarmRelay monitors all M1 alarms 24×7.  After an alarm, I get a callback quickly with information regarding the type of alarm and the zone that was violated.  You should provide AlarmRelay with a list of all your zone descriptions so they can provide more than just a zone number when reporting to you.  If needed, they will call the appropriate agency (i.e., Fire, Police, Medical) to respond, depending on the type of alarm.  They will also let you know about non-urgent situations, such as if the M1 has a low battery condition.  I’ve been very happy with AlarmRelay.