PagerDuty vs. VictorOps vs. OpsGenie>
Reddit
OpsGenie is more or less the same product that it was before the Atlassian purchase. We evaluated these big 3 and decided on OpsGenie as it gave the most flexibility to implement our own workflow. PagerDuty and especially VictorOps seem to have a specific way to handle your scheduling/alerting/response management, so if you have an existing process it will be much more work to adapt.
Link: https://www.reddit.com/r/devops/comments/g34drp/pagerduty_vs_victorops_vs_opsgenie/fnpccl2/