I’m using Windows 8 for software development (web and console applications) on a daily basis for two weeks now. At first I hesitated because everyone says the new GUI is unusable on non-touch devices such as my notebook. However, it didn’t change my workflow at all. I pin all the programs I usually use to the task bar, just as I do in Windows 7. And for all the programs I rarely use, I press the Windows key and type the program name, just as I do in Windows 7. The screen looks different, with all the fancy rectangles instead of the start menu, but input and result are the same, so I don’t care. And when I’m done, I close the lid of my notebook. All in all, I barely notice whether I’m on my Windows 8 or my Windows 7 machine.
So why should you switch to Windows 8? I don’t know. I did because I wanted to evaluate it on my own. Apart from this, there is neither a real benefit nor a drawback. I will continue to use it, but I won’t upgrade my other machines.