I'm sure I am not alone when I say that I have told all my friends who are thinking about upgrading their PC's by getting new PC's, that they should if they can, wait till Windows 10 is out.
I am holding off personally on getting a laptop, till Windows 10 is installed on new laptops by default.
As for Windows 8 being "more efficient" than Windows 7, what good is this so called "efficiency" when many people view Windows 8 to be the new Vista, and refuse to have anything to do with it?