Data point of 1 - we use Oracle in our greenfield platform (in 2018). My reasoning: - our engineers already know Oracle (this is absolutely reason #1). We don'

Data point of 1 - we use Oracle in our greenfield platform (in 2018). My reasoning: - our engineers already know Oracle (this is absolutely reason #1). We don't need to get into religious wars about software, just to write good code quickly. - Oracle is cheap enough for our needs. The price of an oracle RDS instance is immaterial in the grand scheme of things. We are saas so our customers will never be installing our software. - noone ever got fired for buying Oracle. When our customers security teams grill us, running on Oracle and Java ticks one box on their spreadsheet. Same is true if we get acquired. - Oracle is hugely scalable. Even if/when we get super big and successful, we won't need to change our database - there's always a bigger Oracle instance. - Oracle is insanely reliable. In my career I've never seen data loss on Oracle that was not caused by human error. I totally trust that that will be the case going forward as well. - as a company, oracle's not going away. I'm sure some of these apply to postgres as well - but your question wasn't "which is better", which is a much harder question to answer.