QuestDB is a performant timeseries database able to ingest large amounts of data and query in ms. The console UI is also intuitive as easy to use. A lot of the Postgres features are already supported so no need to learn a new query language. I have not tried out other ingestion methods (e.g. influx line protocol), but it's definitely nice to have

I’ve liked SQL query language, easier to start with. Also easy to upload large CSV files and query it quickly.

I was stunned with the performance and simplicity of QuestDB. I am a developer, I looked at the code base and it looks very clean. Moreover they said they took great care to ensure high stability, which is a great choice in my opinion. I was struck by the fact that time-series can be applied to any domain.