We use Datadog across the enterprise for observability of infrastructure, APM, RUM, SLO management, alert management and monitoring, and other features. We're also planning on using the upcoming cloud cost management features and product analytics.
For infrastructure, we integrate with our Kube systems to show all hosts and their data.
For APM, we use it with all of our API and worker services, as well as cronjobs and other Kube deployments.
We use serverless to monitor our Cloud Functions.
We use RUM for all of our user interfaces, including web and mobile.