As a 15 year Sybase, SQL server and Oracle DBA. Oracle compared to the 2 mentioned requires a platoon of DBAs because of the complexities involved. We have all 3 RDBMS and 1 Sybase SQL server DBA can administer 10x what our Oracle DBA can. I'm not even including tyhe Monster OEM 12c Cloud which takes complexity to a new level to include a Gigantic resource Hog. Add cost, Human resources and Oracle is a Huge over glutton Pig!