Uh, it's only the "best" in the same sense that Windows Server is the best server infra on the planet. And arguably Windows has some network bandwagon effect behind its momentum: when your workstation supplier supplies machines with Windows pre-installed and you have built an IT Support Team with the expertise for Windows technologies, it only makes sense to also use Windows in your server.

AFAICT the only thing Oracle has over established FOSS DBs is vendor support and the only thing Oracle has over established FOSS vendors like Percona is a ginormous marketing budget. I'm always grimused when I see Oracle product placement in the MCU.