Ingres and Postgres are the only real Open Source databases out there

MySQL will likely wither and die under Oracle's control.

EnterpriseDB is a costly proprietry bolt-on to Postgres and isn't OpenSource.

Ingres and Postgres are the only real Open Source databases out there.

Ingres is way ahead of Postgres in terms of commercial users and product development.

Postgres currently has more advanced features than Ingres, but Ingres is catching up and performs much better than Postgres.