We're in the process of evaluating ZCM (against SCCM) and I'm wondering how easy it would be to expand the server infrastructure over time? We would probably begin with 1 dedicated SQL server and two primary site servers. Is it relatively painless to add additional site servers and move dedicated functions to them (such as reporting, patch management or imaging)?

I'd also be interested in knowing what infrastructure other sites have in place and what number of clients and users they support.