Last October a friend of mine called me asking me if I could repair his old iMac. I told him that I never opened a Mac before...
It had Mac OS X Panther and Classic installed. I can't explain how surprised I was after 30 minutes using Mac OS X (I had never used a Mac before). So surprising to find that with a 7-year-old Mac you could do pretty much everything, like browsing the Web, email, and such with a very acceptable speed.
I fell in love with Mac OS X. I bought a secondhand Core Duo Mac mini. I sold my main PC. And for my personal use I'll never go back.
Full Low End Mac Article