Short answer is availability - we have three datacenters, and redundant connectivity around the globe. We have 12 of the Fortune 100 as customers for this reason.
Others:
Our phone and SMS alerts read the text of the alert to you, and you can ack/resolve/escalate right from there.
Centralized management of all alerting
If you lose a rack, we wake you up and tell you you have a thousand incidents, we don't page you a thousand times (and DoS your phone in the process)
Super-simple drag-and-drop scheduling
Easy multi-timezone rotations
Fantastic REST API
Happy to elaborate if you're interested - email is in profile.
Guessing a large portion of that funding go towards marketing. They've likely proven that their acquisition costs can scale profitably. They should grab customers before others come along with a similar offering.
Huh, what? One hour of outage for who? What? Context is everything.
Also, this looks really good, but... what does this offer beyond coalescing of alerts that almost any 'enterprise' level monitoring software does?
I'm curious as to how there's $11M worth of work involved in this product needed - plus the $18-36/month/user for ongoing costs.