EnterpriseDB also has an Oracle Compatibility mode--a version of the Postgres database that has an Oracle look and feel to it. Between this and the Migration Toolkit, 95% of Oracle "stuff" should move over without too much trouble.
(disclaimer: I've been working for EnterpriseDB for two months)
Did anyone have some use cases for migrating Oracle to PostgreSQL in context to DWH(Data warehousing ) considering 5TB to 8TB database size (Source-Oracle)