They do all the same stuff with different programs/names etc.

The virus issue is much less a concern, but they could still get one.
They do sell antivirus programs for Macs , so ..

Personally I would rather pay 69.00(for 3 pc's) per yr for a quality AV internet suite than pay the higher cost of a Mac.

Another option would be to install a Linux OS on your windows machine - that would be free and they very rarely get viruses also.