I personally use windows 8. I hate the metro display, but the new task manager and file transfer screens make me nerdgasm. It honestly feels like Microsoft tried too hard to make it look minimalistic, but it suits me.
My family always used windows, and it felt like we went straight from windows xp to 7, with nothing in between. In 2007 I got a (then) brand new Mac mini. Upgraded the sucker up to snow leopard. Honestly it worked well for me. Mac OS X was pretty efficient.
I've screwed around with android, almost exclusively on a nook color. You could get them overclocked to 1300 MHz running honeycomb. So, it was at one point a bit like having a Samsung galaxy with missing buttons and a shittier screen.
I've played with Linux a bit too. I remember using DSL, Kubuntu, Xubuntu, Lubuntu, Edubuntu, Macbuntu, of course Ubuntu, and enjoyed both KDE and Gnome alike.
I use windows. I like windows. It's efficient to me, and is most productive to me. I'd honestly use Linux if any of my machines had anything more than windows-only hardware.
iOS was an innovator that has since sparked a revolution in mobile OSs, from android, to palmOS, to webOS. The features recent versions hold in high esteem, have been available on systems using android for years.
My stepmother's ex purchased something like 6k apple shares back in 1980-something. They of course skyrocketed in value, and after their divorce they split up the shares evenly.
I think macs are just plain overpriced. They boast features that could be had in windows for a fraction of the cost. But, in a perfect world, I'd want a 12 core Mac pro with Linux mint, Mac OS X, and windows all partitioned evenly on a fancy SSD.