[agmiklas]

This is actually one of the big reasons we built PagerDuty. SMS is not as reliable as people think -- messages get dropped or delayed by hours all the time.

We've found the automated phone calls to be a much more reliable way of getting the alert out. We can tell right away that the message has been received by asking the listener to press a button on their phone, and repeat or escalate as needed if we don't hear the tone.