As for me, Fast Ring for Windows Store apps looks much more promising and interesting. Sure, Windows builds is just a base, bare land. App updates is a real news now. BTW, they add native mouse and touchpad interfaces - should it mean that driver's Control Panel interfaces will gone? Sure, i think.
Never appear 14951 on my system, however WU found 14955 at first try, well, certainly there is something wrong with ms servers