The Metro/modern/manky UI sucks big time.
In an attempt to ape simpleton iOS, MS have taken for granted, the eminently usable UI of Windows past and lost 90% of what made it slick and usable.
Abandoned and lost are logical keyboard shortcuts, mouse shortcuts, vibrant and distinctive colour schemes and layouts.
Instead we have bland plain window backdrops with no borders and no colour. Open up a handful of randomly overlapping windows, and it becomes impossible to tell where one starts and the other ends.
Even the OS itself has no impressive, consistently clear style guide any more. What hope is there for "apps"?
Instead of building on the efficient and usable UI it had before, we see half baked redesigns of a bad idea again and again with apparently no usability testing whatsoever.
Whoever's in charge of this mightily clusterfluck should have their atoms strung out in a long thin line and sent towards the nearest black hole.