I think Microsoft's main mistake is pushing people into the new Metro UI on the PC. It should be totally optional in Windows 8. Maybe in Windows 9 or 10 when there are more Metro apps available and the kinks have been worked out they could make it mandatory. Pushing people into this half-baked solution right now is a terrible idea. From what I've seen the Metro GUI on the PC requires extensive use of mouse gestures, mouse hovers, and keyboard shortcuts. I really don't think that's going to work for most people.
Download and give it a shot. It's actually very functional to use. The thing is if you are on a laptop or a desktop, the metro mostly shows up when staring an app. Otherwise it mostly stays away.
If you are on a touch based tablet, you are mostly using metro all the time. It actually works for most people.