Windows 8 - destined to be the next Windows ME or Vista. We installed it on a laptop at home and really regret it. The laptop mostly sits unused now until I have time to reformat it AGAIN and go back to Windows 7.
The audio is absolutely terrible, no bass, all mids and this absolutely ear-grating treble. I know it's an audio driver problem, but HP is a terrible vendor in that they rarely release drivers for new operating systems if your hardware is older than 6 or 8 months. So you're stuck with the Microsoft drivers and I mean, really, it's horrible, everything is unlistenable. Everything has this fingernails on the chalkboard type grittiness to it. That alone is enough to reject the OS entirely.
It's difficult to find your way around to do what you want to do. If I want to run a program, why would I want to have to remember if it's on the desktop or in the metro interface? I understand they want to make a somewhat seamless user experience between phones, tablets and traditional desktops/laptops but it really makes more sense for the phones and tablets and no sense at all for desktops.
Also, I'm not surprised to hear IE10 has compatibility issues. The hardest thing when building a website is getting the CSS right for all browsers and then also having to adjust it again just for IE, because Microsoft refuses to follow the international standards for CSS.