> If you don't mind me asking, how is the SQL Server as far as price goes?
You can use this to get a very ballpark idea:
https://wintelguy.com/mssql-ent-licensing-calc.pl
From actual quotes at full price, we'd be paying around the same to Microsoft for SQL Server Enterprise than we were paying Oracle BEFORE the price hike/license changes. However that doesn't include discounts which most organizations running any Microsoft software at all would be eligible for.
So in other words: Almost always cheaper than Oracle Database. Varies between a little cheaper and substantially cheaper. Both companies are trying to drag you towards Cloud however, so there's deeper discounts there right now (it's a trap!).
> Also curious, what made you decide not to use PostgreSQL (or EnterpriseDB if you need entreprise solution)?
No one person decided. This is a large organization that moves slowly and is fairly conservative. Plus the costs of migration are high, if migration fails people in management will suffer (either to their career or just outright be transferred/fired).
So in other words "nobody gets fired for buying Microsoft" or w/e. It certainly doesn't hurt that it is much easier to hire/contract in SQL Server talent than PostgreSQL. Technical considerations play a part, but only up to the point where it has to have what we need.
> I am asking because I have mostly used MySQL (pre-Oracle) and now PostgreSQL, and have always wondered what made people choose either Oracle or SQL Server.
That's because you're considering what is best using logic, reason, and technical facts. In the enterprise space more often than not major companies just follow the crowd, with a handful of trailblazers setting the standard. Oracle and SQL Server are popular because they're already popular, in a fully circular way.
If I started a business tomorrow I'd use PostgreSQL. But if I was a C-level in an enterprise and my career is on the line, I am going to be sticking with SQL Server.