Running an open source stack means you're not completely at the mercy of someone else. I'd cite Windows 10 desktop editions as a paragon of "you buy it, but you

Running an open source stack means you're not completely at the mercy of someone else. I'd cite Windows 10 desktop editions as a paragon of "you buy it, but you don't own it, then you suffer" proprietary products, but it's not a server component. So I have to cite FoundationDB, the proprietary database, which was seriously awesome, but so awesome that the downloadable binaries vanished overnight. I have at least the assurance that such a thing cannot happen with Postgres (there are a multitude of for-profit companies working on it full-time, in addition to pro-bono community contributors), or with Apache Cassandra; and it's a similar assurance that keeps users of RethinkDB able to continue to operate despite the company being bought and folded. ---- Other advantages of open source: the very freedom to inspect and modify the software we run. This freedom is how OpenResty was born. In fact, Postgres itself comes from another GPLed database. On a minor note: this freedom is what allowed us at my last job to create a patch for an internally required function in Nginx, in ten minutes. Had Nginx been closed source, we'd have had to request the makers, wait days/weeks/months, and if accepted they'd include it.