DataDog provides Cloud-Scale Monitoring as a Service and offers one of the most competitive monitoring solutions in the MaaS arena. It comes at zero price on up to 5 hosts. DataDog integrates with virtually anything, with a 100+ and counting integrations available, meaning it can be easily integrated into almost any platform. It's been adopted by several high profile businesses such as AirBnB, Samsung and Electronic Arts.
We recommend and use DataDog here at Cake mainly because of its easiness on adoption and richness of features. Datadog also integrates with other services and platforms we regularly use at Cake such as:
Datadog also allows for the creation of customisable dashboards, so we can create a dashboard which will show exactly what it is you need to see from a monitoring tool.