Hard question to answer because each solution is unique and has its own tradeoffs. Taking a step back QuestDB is a less mature product than the ones mentioned, and therefore there are many features, integrations etc. to build on our side. This is a reflection of how long we have been around and capital we have raised versus those companies who are much larger in size.

If you are already using Postgres, then TimescaleDB is a natural fit - not having to deploy and manage a separate service is a real boon. You can also join with non-TimescaleDB tables, so if you need to combine time series data with regular relational data, that's another advantage.

OLTP is not a good fit, if your workflow consists from INSERT/UPDATE/DELETE statements