SQL Server was very good and used in a lot of enterprises. ime the decision between Oracle and SQL Server tended to be down to whether the IT department or company was a "Microsoft Shop" or not. There were a lot of things that came free with SQL Server licenses and it had really nice integrations with other Microsoft enterprise systems software and desktop software.

Oracle was definitely seen as the more mature and resilient (and expensive!) RDBMS in all the years I worked in that space. It also ran on Unix/Linux whereas SQL Server was windows only. Many enterprises didn't like running Microsoft servers, for lots of (usually good) reasons.