Eller asked for reasons he could present to the board that showed the advantages of a dual platform approach. MacCentral readers sent him LOTS of information, which Eller kindly shared with us. But he says he doesn't need any more info. We allow the staff to choose the platform that best fits the need.
Consistency is the key.
I have found that the Mac's are by far an easier platform to support. There is NO registry, no win.ini, no autoexec.bat, or config.sys files to contend with. This allows us to support our district with only three full time computer techs. The 'battle' of one platform over another is mostly in the minds of the adults, not the kids. I do almost all the support myself.