Had good results with echarts. With Superset not so much: complicated to install, lost all dashboards after an update, cryptic error messages, custom queries meh: we decided to use views in Postgres. The project with Superset was finished successfully, but the time spend is a multiple compared to using something like Power BI.

All in all, not very innovative, but highly needed open source version of a traditional BI tool. Definitely something to follow and to use in temporary, not too demanding use cases. And hopefully a future replacement of Tableau or Power BI.