I started with Macs, switched to PCs, originally to take a bunch of programming courses, but stuck with them for maybe ten years, then back to Macs. I've always liked the quality of their hardware and with OSX, the interface got better. Problem was I still couldn't run the CAD and CAM appications I need, until they switched to Intel processors. Now my little notebook runs most of the stuff I need under OSX and I run CAD and CAM in Windows under VMWare Fusion. Life's good.
I too have taught many, many people how to use computers, both PCs and Macs. The ease with which people learn and use computers has much more to do with their own fears and limitations than which operating system they're using.
Yup! Macs face far fewer threats, but it is certainly not none.