Hey! Chartbrew owner here

Grafana is an amazing product and offers a lot more features than Chartbrew. The main difference is that grafana focuses on monitoring performance metrics and Chartbrew is more tailored for business/product metrics.

Also, quite a few of our customers use Chartbrew because of the Firebase integrations

I am currently looking into charting / business intelligence solutions, so I took a quick look at this one too.

What I prefer here over Grafana is that it seems to be written in plain JavaScript. Which would make it much easier for me to customize it / contribute to the project. Grafana seems to be a mix of TypeScript and Go, which means compilation steps before you can see changes in action.

Good questions. I couldn't find much difference. Maybe it's that they can host it for you.