I have hoped on using Druid very early in the day, using it from early 2018 , the potential it unlocks with all the easy to use and inbuilt capabilities of looking at different analytics perspectives is amazing. All the options of flexible filters, approximate algorithms, exact calculations etc makes our life lot simpler.

Ease of use. Both inserting the data through Kafka or querying, both were pretty intuitive.

The ability to power realtime dashboards well, and ofcourse that its open source (so I can skip messy accounting approvals)