I am a DBA originally started with Oracle 5 and have 13 years of experience using Oracle database. For last five years, I have also been using and administring SQL Server. In my opinion both have pluses an minuses of their own. Here is the comparison between the two based on features you are looking for.
FEATURES ORACLE SQL SERVER
Manageability Difficult Easy
maintainability Expensive Cheaper
scalability Highly Scalable Scalable
performance Amazing Good
availability High Acceptable
security Superb Good
app development Sup Best OK
In short, it all comes to funding for a project and if you do not have any funding problem go for Oracle. If you have less than 50 users go for SQL Server and if more go for Oracle.
If you have any other question feel free to ask me.