I use Windows 8 at work. If you're using Windows 7, you might as well continue using it.
Windows 8 have the new Metro UI (also later called Modern UI) which is designed for touch interfaces.
It's probably alright for tablets and smartphones but it really is unsuitable for a desktop or a laptop.
I think the Metro interface in Windows 8 decreases usability and makes using the computer cumbersome, annoying and frustrating and kills productivity.
Windows have no start button, no start menu, and now features a fullscreen start screen instead which makes the brain do a context switch and lose focus which messes up the work flow and reduces productivity.
If you're going to use Windows 8, then I can
strongly recommend Classic Shell which is a free, open source software that gives you a start button and a start menu and makes Windows 8 feel and behave more like Windows 7. This makes Windows 8 more tolerable and less frustrating.
http://classicshell.sourceforge.net/