PagerDuty

I tried a competitor's product which was a free notification manager up to 11 people. It took me 3 days to get anywhere with a basic task of integrating 3 of our noisiest alerts. Then I tried the PagerDuty trial and got 2 of our noisiest alerts built out in 1 day. I added 3 more over the next 2 days to go well over the targeted mark. Coworkers were excited to help put time and effort into the system as opposed to the free tool which I couldn't seem to get any traction with. The alerts were immediately available, they were easy to get posting to my cell phone, and adding additional users was a cinch. The tool unfolds and becomes more useful the more time you put into it where some tools you struggle to get right and then you're afraid to make changes.

The UI is a bit quirky in the scheduler which is a pretty important view if you have a rotating on-call shift you're trying to tie down. There was a lot of "can't delete before you delete elsewhere" scenarios where there could have been a "will also delete these elsewhere, are you sure?" scenarios. What you gain in ease of use and stability in the mobile platform you lose in overall functionality, it is simple almost to a fault and while it seems silly there's no skinning of the mobile app to better suit your personality in a hyper-customized world. I'll know shortly if they're willing to go longer but they seem to be sticklers for the exact trial length + only a little. Corporations interested in putting in a full month long or longer trial that may need that amount of time to show value, create a SOW, and have a PO issued may be stuck in limbo for a few weeks.

PagerDuty is incredibly easy to setup and use. Creating new teams, on-call schedules, and escalation policies can be done in a matter of minutes. You can go from manually looking up people via a google calendar or an excel sheet, to engaging an on-call resource in 2 minutes or less from the great app while you are on the beach.

The integration with Slack is great, no other way to say it. Very useful for incident notifications for those teams that rely heavily on Slack.

The reporting functionality of PagerDuty needs some further enhancements. Obtaining certain data such as "what users are using which contact methods" for example still needs to be provided by contacting their Support team. The filtering of the Visibility console needs work and is currently limited to "All Teams" or a single team.

Simple setup and easy first alert.
Comprehensive incident management, reporting and analytics to focus on what matters.
Highly configurable alerting that is controllable by the recipient themselves.
Easy escalation, resolution and communication features in mobile application and via the web.
Well supported SMS and Phone alerting and incident management - Internationally
Quick and easy support for the product - from a great PagerDuty team.
Less noise, more actionable alerts with comprehensive de-duplication and alert filtering options.

PagerDuty is unforgiving of poorly written interfaces generating errors and despite ignoring ones' phone while in meetings, the alert will get to you, no matter what you are doing!
While I love the 'PagerDuty' alerting and am amused by the 'Engineer Laughing' alert sound - having more options for custom, per incident, alert notification sounds in the Mobile app would be great.