I like how you can easily add new columns or tables without having to worry about compatibility issues between versions of Druid. You have to be careful when adding new fields as they may not work well with older versions of Druid (e.g., if you're using Spark). The UI could definitely improve - there's no way to filter down rows after searching through them. Also, sometimes searches don't return results even though you know you should get some back. We've been able to solve our problems related to ingesting large amounts of streaming data into Druid. This has allowed us to build dashboards quickly which allows us to make better decisions faster. Our business needs are driving this project forward so we'll see what happens next! Using Druid we were solving two key problems: 1) How do we store and analyze billions of events per day? 2) How do we visualize these events in near real-time across multiple users and devices?