Using Pushover for this and fairly happy. What sets this apart?
However, what sets this apart in my mind is:
* The web interface. Maybe Pushover has this, but I haven't seen it.
* The MyNotifier web app seems clean and simple.
* MyNotifier would solve a different problem than pushover for me. Pushover wakes me up in the middle of the night when UptimeRobot tells me the site is down. MyNotifier could be a softer/gentler way of collecting important but not critical messages.
For $6/month I'll likely give it a try.