Postgres is a better choice for 99% of the companies out there. But there are cases where you need ability to massively scale AND control your database cluster perfectly.

Postgres won't even let your force an execution plan and ignores hints (yes, there is an extension for that) so your optimized query can at some point just 10x in execution time and increase load in production when the plan changes.

In Oracle, I am told you can prioritize certain queries at certain time of day - it's crazy what it can do. Yes, it's slow and expensive. If you have money to throw at the problem, it's fast and it solves your problem, whatever the scale. Their Exadata cluster, for example, is wicked fast storage layer pre-filtering the data it sends to the database.

Of course, I despise their business practices - especially the abuse of customers via audits. As a database, it absolutely has its place regardless of lobbying, corruption, and whatever else they are doing.