I prefer it over MySQL or MariaDB because you can create several databases with many schemas. It needs to be able to cluster.
It is an open source solution and that is a database engine very powerful. Besides it is highly configurable. I prefer PostgreSQL over MySQL or MariaDB because you can create several databases with many schemas and create roles like owners, and not only grants over tables, or procedures. On the other hand its very easy and intuitive to administrate the connections by hosts, databases, and roles.
Improvements to My Organization
PostgreSQL is a powerful dateserver although not like Oracle. So we can make many developments in a cheaper way with high availability. Besides, its very useful tool for debugging with a soft learning curve.
Room for Improvement
It needs to be able to cluster. We have implemented the high availability with a master-slave mode and one host in only read mode. This is the worst feature of this product and the quality sign of Oracle.
Use of Solution
I have been using PostgreSQL server for three years.
The upgrade from v8.4 to v9.3 was a little hard, but this was executed finally well.
We had no issues with the stability.
We've had no issues with scaling it for our needs.
Customer Service and Technical Support
I've not had to contact them.
I use MySQL, MariaDB, and Oracle. I chose PostgreSQL or others depending of the project. For Java implementations I prefer PostgreSQL, and for PHP development, I prefer MySQL or MariaDB,
In my opinion the initial setup is easier than MySQL because it is more intuitive, but you must to edit a couple of config files, and become more aware of the entire infrastructure.
Pricing, Setup Cost and Licensing
It's open source code, so you get it for free and need to contribute to debugging errors and improving the code.
Be patient! Like most open source tools, this requires commitment and a little knowledge.
* A fragment from postgresql.conf
* How to access to database-server using psql client, and create a database
Create a user/role and be owner for a database. We can list all databases with "\l".
Disclosure: I am a real user, and this review is based on my own experience and opinions.