I have not tried Quest Central, however I do use Embarcadero's DBArtisan.  It works cross platform for DB2, SQL Server, Oracle and Sybase.  I have used it for both Oracle and SQL Server and really like it.  You would have to talk to a representative about pricing though.  I know they have individual workstation licenses and server licenses at various prices.  Their web site is http://www.embarcadero.com/ for more info.