The DBMS technology is excellent. I worked at Sybase from 1990 on and much as I loved the company Oracle beat us fair and square with features like Row Level Locking and Multi-version Concurrency Control. Oracle also had a healthier attitude about data corruption. Oracle fixed the bugs or didn't let them get in in the first place. Sybase on the other hand developed DBCC, which repaired the problems on live databases. I lost numerous tables on Sybase while developing products. This never happened after switching to Oracle in the late 90s.
One of the things I still like about Oracle is that no matter what data management problem you are solving there is generally some feature that helps you do it.
VPD (virtual private database) is a great example. I was working at a SaaS in the late 90s and we ran into a problem where we absolutely needed data from multiple tenants in a single database but still fully isolated between each tenant. Oracle had a feature called VPD that did exactly that. It saved our bacon on that project.
I have dealt with the Oracle license police and yes they can be jerks. But you can't fault their technology. The company deserves respect for what they have accomplished.
Edit: fixed typo.