After all bickering and complaining (often not without good reason) I thought it was also time to add a positive note about SW. I think they did listen a little and posted the SW2004 Reference Guide in pdf format in the Subscription Area called "ReferenceGuide_ENG.zip". Almost 1000 pages of searchable data on how to use SW2004 or how it is supposed to work.
cheers,
Elmar
P.S. A VAR told me that the reasons for SW using WindowsInstaller has to do with Microsoft Certification. Believe it or not, especially if you need to administer 150 or so computers