Based on our experiences I have to agree.  We have both AIX and Windows TSM
Server.  The call support is indistinguishable, both very good to excellent
depending on the problem.  Windows TSM Server has had a tremendous number of
feature improvements over the last 18 months.  Particularly in the
performance arena.  To me the only limiting factor is the hardware
architecture of the Intel platform now.  Not that Tivoli supports one or the
other better.  The install processes have been greatly improved with the
last couple of releases as well.

In general, I see the storage area of IBM and Tivoli focused on the Windows
platform as strong or stronger than any other platform.