I am starting to get my head around building applications for Microsoft Office / PowerPoint, and this can be done easier on a Windows machine, so I am now pretty much all day working in a Microsoft environment on Apple hardware. (Don't worry, the result of the effort will run on Windows and Mac).
The whole Windows experience is fantastic and completely at par with a Mac. As I said in a post before, I now consider PowerPoint to be a better presentation program than Keynote, and PowerPoint for Windows is better than PowerPoint for Mac.
The only issue for me is to get the Apple keyboard and mouse properly integrated with the workflow (scroll directions, knowing where certain keys are, and getting used to the difference between CMD and CTRL). (And... the Logic Pro X music software does not run on Windows).