I started using Datadog two years ago, for a simple Reddit scheduling webapp I was building with Spring Boot. 
I moved away from what I was using at the time (ELK - Elasticsearch, Logstash, Kibana) into Datadog and had data in and a useful dashboard in about half an hour

Going from monitoring my infrastructure by hand to having these deep, crazy powerful integrations - pulling in the data I needed from every layer of the system (I was running Tomcat on AWS) was a huge step up.  

After that, and beyond my teaching project, the thing that made the platform work for me - is the way it scales
The clients I work with typically have complex, widely distributed systems, with heavy containerization, and the tool needs to have full, native support for all of that. 

Datadog handles all of that and lets you intelligently dig into data - visualize it, sort it, filter it, correlate logs, and basically understand events. 
Best I can describe it is - elegant
It makes them really easy to recommend. 

In case you've missed the mentions in the Java Weekly, definitely have a look at the platform

>> Try out Datadog

Enjoy and let me know what you think, once you're up and running. 
Cheers and stay safe,