SQL-Server and MapServer

[Stefanie Weykam]

Hi list members,
Does SQL-Server have a spatial extension? How does it perform?? (..compared
to PostGIS?)

I have talked with a couple of biologists who do not use GIS (yet) but
maintain a nice database with a lot of interesting spatial data which they
would like to serve as maps on Internet. The database will be very
frequently updated and the application will include spatial queries.  

These guys have come from Access and ADO to SQL-Server using Visual Basic
and .net and seem to be quite happy with it. So, -as far as  possible- I
would like to avoid making them change their familiar environment. Although,
their database design is still under development, so this might as well be
the chance. 

After a quick look at the archive, google and the SQL-Server home page, I
haven't found many references (some on TerraLib and little else). 
I suppose the few hits indicate that there is nothing for SQL-Server that
comes close to PostGIS. Could somebody provide me with some good pro's and
con's on SQL-Server, please?

Thanks in advance,
Stefanie