I've been running Windows 8 since they release the RTM version to TechNet subscribers on my primary laptop (about a month now). Short version - outside of Metro it's basically Win7SP3 and it works great. Metro is every bit the usability disaster that people have claimed when not running on a touch screen. The good news is that you really don't have to interface much with Metro at all. It replaces the start menu, but…
Beyond that, we were developing interception technologies to hook inside windows 8 metro applications successfully.