First thing to do is this :
Overall I like it. I don't care about Edge browser (I support a law firm as IT director, and there are a number of critical business and cloud services sites that don't function with it) or Cortana as it currently sits, but that doesn't mean that Windows 10 doesn't work just fine.
I even had no problem with Windows 8/8.1 once about 30 seconds of tweaks were done (Classic Shell + set default PDF to Foxit or Acrobat, etc).
It's brave of MS to give away W10 for a year and I think that will help DX12 take off much better than if they used their old business model.