I've been using Windows and Mac concurrently ever since getting the 2007 aluminium iMac. Which is still, somehow, working fine albeit a bit slow. My current PC is one that I built myself back in 2011. I think the difference between operating systems is not as big as you think it is. Maybe it depends on how tech-savvy someone is or isn't, but Windows 7 has almost never caused me a lot of trouble. Not a spotless record but nothing that a bit of Googlefu couldnt fix. Hell, the only virus I ever got was incredibly lame malware on my Macbook Pro. I'll grant you that user experience design has been much better for much longer on OS X but even that advantage is slowly being eroded. (Case in point: iTunes.) In that respect I even think Android has surpassed iOS.