99.99% of the planet uses windows for work, including most government bodies, and fortune 500 companies..
And trust me, i work for "a leading world wide payroll company" in the IT Department and i find it laughable that our "web based" products still don't support browsers other then IE version 7,8 and 9... no chrome, firefox, or even IE 10 and certainly no tablet or phone support)
However none of our "huge" client base, including people like Amazon, Ebay, several banks, and many other "well know multinationals" all run Windows at a corporate level.
My "go to operating system" for anything i want to do is still Amiga OS, i have a beefed up Amiga with PPC chipset and its still a joy to use over anything else thats been along since.
i use my Mac for video conversion and storage of a rather large iTunes library (TV Shows and Movies, currently at 11TB and change stored on a Drobo B800fs)
as for using an iPad for work, nahh, its ok for checking on things, or making last minute revisions, but id never be able to create a document on it that i could call client facing in anywhere near as short a time as i can on a PC.,
Tim Cooks a kook if he thinks people don't prefer a real, mechanical keyboard and mouse over a touch screen for productivity if they are doing anything more than sending a short text or making a single line revision to a document.