1) It runs better than Windows 7 under da hood, plus ISO image auto-mount 2) Interface is shit (Release preview: No options for personalizing interface (sans 3rd party software) AT ALL) and inconsistent as fuck. Me no gusta. 3) Programs don't auto-run as admin when you're using admin account. What the fuck? 4) Bootloader is full of shit. First it loads whole OS, then it offers you OS choice. (That's why you're installing your systems in this order: Win8, Win7, Linux from live CD)
And that's why Kubuntu (or any Linux distro with KDE) is far better choice. (Note: I'm not talking about distros with Unity or Gnome 3, because they suck and are even worse than Win8 (interface-wise).