We use the Mac Minis at the school for classroom and videoconferencing. They're great for their size and portability and you can load them up with RAM and have a pretty powerful machine. That said, they cost quite a bit in comparison to PCs. For the same funds or less you can build a really nice PC or pay for a high end Windows laptop.
Of course you can run Windows on the Mac Mini as well, so having both OSs to choose from is an advantage. Just remember, if you go with the Mac Mini and lots of RAM and want Windows in Boot Camp mode, install the 64-bit version of Windows to make use of the RAM.
"I know rocks. Rocks are hard."