Platform comparison ...

Hello Group,
I need your help, in putting together a list of comparisons, and good solid technical reasons, to why to use PostgreSQL over using Microsoft SQL Server. Right now, we are using PostgreSQL for a back-end for some of our web stuff. A couple of our developers, which are Microsoft VB developers, are complaining about not being able to use proprietary MS stuff with PostgreSQL. I have told them to use standard SQL92 compliant programming techniques, and all will work just fine. They just don't seem to understand why a person wouldn't use SQL Server. If I could put together a list of good solid technical arguments, (Performance, Support, Reliability, ETC.), as to why PostgreSQL is better, I think I can make a good case in keeping PostreSQL. I just don't have any SQL Server experience to compare with. If any of you, who have SQL Server experience could send me good technical comparisons of SQL Server vs PostgreSQL, I would greatly appreciate it.

Thanks in advance,
Dale Anderson.