Can you talk more about why you should use Postgres unless you have a compelling reason not to? I'm currently investigating options for storing high-frequency data. Postgres is looking like a good option.
Additionally, often we believe our application needs feature X, and there is some database tech that purports to excel at X, the fact is postgres is probably able to do X unless you get to some extreme velocity or volume. Furthermore, by going with another database you are almost always giving up on features W, Y, and Z that you don't realize you need that Postgres supports and isn't supported by the "Exotic" database you are thinking of.
In short, Postgres has amazing breadth and depth in features and support and tooling. Be sure you are ok giving that up!
This btw is one of the reasons I love Postgres - its extensibility.
(Disclaimer: TimescaleDB cofounder)
I would say, Postgres is not too storage efficient in itself for large amounts of data, especially if you need any sorts of indexes. Timescale basically mitigates that by automatically creating new table in the background ("chunks") and keeping individual tables small.
When compression is enabled, TimescaleDB converts data stored in many rows into an array. This means that instead of using lots of rows to store the data, it stores the same data in a single row. Because a single row takes up less disk space than many rows, it decreases the amount of disk space required, and can also speed up some queries.
(Timescale employee)