I made that leap too (moved from a company that used Pagerduty to a company that used Opsgenie) and it is the same feature set but not the same quality. Pagerduty in my experience is rock solid - I used it on various high-page-frequency rotations for something like seven straight years and literally never saw a dropped alert/notification once.
On the flip side in the 8ish months I used Opsgenie I saw a litany of issues, like the mobile app silently logging people out (and thus not delivering push notifications) and the app failing to send SMS notifications. We had pages get dropped by the primary because they never got a notification.
I want exactly one feature from my pager, delivering 100% of my pages. It's not a situation where I'm ok with 99% success rate, and that seemed to be the tradeoff and what you are paying for with Pagerduty.
On the flip side in the 8ish months I used Opsgenie I saw a litany of issues, like the mobile app silently logging people out (and thus not delivering push notifications) and the app failing to send SMS notifications. We had pages get dropped by the primary because they never got a notification.
I want exactly one feature from my pager, delivering 100% of my pages. It's not a situation where I'm ok with 99% success rate, and that seemed to be the tradeoff and what you are paying for with Pagerduty.