MSSQL < Oracle?
No way. Maybe Postgre is nicer than MSSQL for you. I don't know. But Oracle? Oracle is worse than MSSQL in just about every way that matters.
Why?
Free + Fast + no weird syntax (like Oracle) + Most features (although I think Oracle replication might still be better)
Oracle replication usually requires Golden Gate to the best of my knowledge. Someone was telling me the other day they hacked their own system together with shell scripts (ship and restore log files using scp etc), but that's probably not something you'd want to build your business on.
So yes, Oracle replication is probably better if you use Golden Gate. But Golden Gate is pretty expensive (17k per CPU?).
MySQL < MSSQL < Oracle < PostgreSQL.
Basically PostgreSQL is king of relational databases right now.