I'm only somewhat acquainted with Oracle, enough to form an opinion without forming an attachment. In my opinion, Oracle has a lot of "junk in it's trunk" dating back to the 1980s; a lot of cryptic sysadmin commands, old-style SQL syntax, and backward compatibility. In contrast, MySQL is new enough not to suffer from that affliction, and Microsoft periodically deprecates obsolete features from SQL Server (which in my opinion is a good thing). From the perspective of someone coming in new, Oracle's commitment to legacy support is a negative; it makes learning the product more difficult.
"The universe is complicated and for the most part beyond your control, but your life is only as complicated as you choose it to be."