Oracle is the database to beat in terms performance and features or at least is positioned that way. More importantly, if you are thinking of migrating from Oracle to Postgres to save money, you need to know that your new database has at least the same features at the one that you are moving from.
High availability is one of the most important concepts and features for a database system. For most enterprise level applications, downtime has a direct financial cost and the actual loss of some or all of your data would be catastrophic.
You need to know that the system that you are moving to can protect your data as well as the system that you are on at the moment.