> On top of that, it's the best NoSQL database currently available.
Surely that depends on the load? From what I understand Postgress isn't easy to set up when the data spans more than one server, which many NoSQL database do actually handle fairly well.
If less frequently used parts of it don't fit, offload to disk.
Ideally, the DB should guarantee data integrity after a crash even if the DB is served from RAM.
That's the ideal scenario: You have the best of all worlds.
Coincidentally, that's exactly what Postgres does.
On top of that, it's the best NoSQL database currently available.
Of course, you can use it with SQL if you ever feel the need.