I don't know much about the Mini but it was made even cheaper to upgrade this last week. I have a Powermac G5 and that was my first mac ever. im glad i switched. My roomate has windows XP and his computer gets viruses he has to update it practically daily due to all teh security threats and what not.
I have never had any problems like that, no computer freezes, no office crashes, no nothing. Office is even better on mac, Microsoft even admits it. Too me its really stupid to go with a wintel machine unless of course you just cant afford a Mac. But in reality you get what you pay for with computers. If you buy cheap you get a crappy computer (At least with wintels).
Wintels are my bed and butter. I am merely branching out.