It isn't a compelling purchase at all, nobody will go out and actively seek a Windows 8 device, and desktop / notebook computers have had decreased sales since everyone has one now and they are "good enough" for media consumption and text / spreadsheet editing. The only reason anyone needs more horsepower now is for graphical horsepower for animation or gaming or computational horsepower for compiling or running a server.
So nobody wants Windows 8. It is a product without a target market, and the Surface has fallen flat on its face as a one trick pony to try to corner a "market" on a tablet with a desktop.
And hopefully in a year we have a mature Ubuntu running on Android tablets just fine, and that IMO will be a much nicer desktop experience on mobile than Microsoft Window and the Windows 7 desktop at 7". Except for a tiny, tiny market of businesses that will buy surfaces for their employees to use the mobile versions of word and excel I don't see this train leaving the station.