I have a pretty high spec laptop that started giving me a few issues after two years running the stock Dell Win 7 install. The final straw came when it wouldn't go into sleep mode. I bit the bullet, cloned the drive and then wiped it and loaded Windows 8 CP.
At first I was totally lost without the Start button and Control Panel, but eventually I started to 'get it'. Yes the Metro interface feels 'out of place' on a laptop/desktop, but it isn't unusable, just different. I treat it as the 'real' start menu, and it seems to be getting into my head. I've always been a lover of keyboard shortcuts, so learning a few new one's has not been a chore.
The big bonus has been the improved performance. This is a Studio XPS laptop, quad core i7 720QM Clarksfield CPU, 4G memory, 16" HD RGB LED screen, ATI 4670M gfx and a Samsung SSD. It comes with a 9 cell battery as standard and running windows 7 I could barely get 2 hours out of it, running windows 8 I'm currently seeing over 3 hours of web-browsing and email etc., Nothing taxing, but I'm comparing like with like here. It also boots ridiculously quickly, the log-in slash screen is there in seconds, and it shuts down equally quickly, once you've found the well hidden icon that is!
I'm looking forward to being able to buy a tablet with proper Windows usability, memory card slots, USB connectivity and the ability to run my PC programs, I will definitely hold off the iPad purchase now, even though I love my iPhone. Windows 8 may have compromises (as all OS's do) but I think it shows promise and isn't as bad as it has been painted.