Why does everybody keep calling this an "upgrade". Win 8 is most definitely a downgrade. Start menu - gone, multi-tasking - gone, ease of use - gone, aesthetics - gone. Why willingly pay for less features and more frustration?
The problem is a lot of people assume the latest and greatest is always better. So those who just dive in and "upgrade" are going to sorely disappointed and want to go back to Win 7 immediately. A few will stick with it and fewer still might even like it. But I'll be sticking with Win 7 for the foreseeable future, especially on my HTPC.