This is the vaulted Windows 8 OS? Looks like a tablet or phone OS to me, not a full fledged PC OS. Not to mention it seems a little early for Win8....
If I remember correctly, people had problems going from XP to Vista (Not only because it SUCKED, but it also had several 'radical' UI changes). My mother is like the majority of PC users, they hit the power button, log in, and click internet. Then they go to the few websites they goes to, and shut down. She had problems adjusting from the old XP PC to the new 7 PC, who knows what will happen when the UI changes this much! Its one thing to have changes in a UI, or radicly change it (Like Windows Phone 7), but this doesn't look like a good change.