As the name says, it's a simple way to notify systems
What do you like best?
It's a simple way to send notifications via a suite of different avenues — push notifications, email, ... It has a robust API as well.
What do you dislike?
The organization of push-notification devices and topics, for some use cases, can be a bit opinionated... but it can be adjusted to fit most workflows.
Recommendations to others considering the product:
Consider using the API for orchestration of device registrations, retry policies and other features. It is most robust.
What problems are you solving with the product? What benefits have you realized?
Push notifications, email notifications, webhook-dispatchings.