Many of our customers ask us this question so we thought we'd lay down our thoughts.
The last couple of our articles have been how to do this and that in PostgreSQL, SQL Server, MySQL or having PostgreSQL coexist with an existing SQL Server install.
A major reason for that is that in many of our projects we have a choice of what database to choose for a new piece of an application as long as it can play nicely with the existing infrastructure.
Our core database competencies are still PostgreSQL, SQL Server, and MySQL with it leaning
more toward PostgreSQL each day. We are perhaps somewhat unique in the PostgreSQL community in that Oracle never comes into our equation of decisions (though Oracle and PostgreSQL are perhaps more similar than the others).
Oracle is too expensive for most of our clientele
so it's a non-issue, and when our clients do have Oracle -- it's thrust upon them by thier ERP/CRM vendor and is essentially off limits to them.