To be serious, my work required a Windows for the last 5-6 years. I just installed Ubuntu about a month ago and the progress done during those years has been amazing, everything worked out of the box, and worked better than on Windows.
Unity is pretty bad and Gnome3 wasn't working for me, but I just came back to Gnome2 and it's been working really nice. I have everything I need on my tiny desktop and no stupid bugs. Only problem was with my second monitor that I couldn't get working in other than mirror mode. I had Xinerama a bazillion years ago and could make it work with every setup, but now that I didn't have to touch the config files to make everything work, I didn't want to.
But 200M users? Not very likely