We use SpecOps Deploy and Microsoft SMS 2003 here at Bloomsburg University.
We're in the process of transitioning from SMS to SpecOps Deploy completely, since it's so much easier to use and support.
Since it's based of Group Policies, it's very easy to see what machines / users in active directory is going to get this deployment. We've been using it for a few years now, and it's just wonderful. It lets us use MSI files and MSP patches with ease, and still kick off the setup.exe with command line switches for things like Adobe CS3 and Office 2007...
I'm very happy with this purchase for our University!
--Bill