Of most of the "hate it" reviews I've read, the person didn't even give it a chance, basically refusing to learn how to use it. It took me all of 15 minutes to figure out most of it, as it is very similar to Windows 7 or XP in implementation. Granted, I learn faster than most, especially when it comes to logical/technical things, but I doubt it would take anyone an hour to learn it, if they gave it a chance.
Figuring it out on a touch screen is still giving me a bit of trouble. (I have a WinRT tablet, which is basically the same interface.) I haven't figured out how to "right click" with a finger gesture on the desktop to bring up item properties or the task manager. I really don't see how this is supposed to be a "tablet interface" when I can't do so many things with the touchscreen. It's far easier to use with a mouse.
Right click on tablets is usually replaced by "click and keep pressing" just fyi.
Btw there is another issue there, they do not differentiate between a tablet input and a touchpad input, gesture wise, which makes it a real PITA when your laptop is touchpad based with Windows8.