I recently made a jump to Windows 10 and while it seems pretty cool and I like the Xbox app so I can keep up with my old Xbox Live friends from my 360 days I don't in any way see Win 10 as a serious alternative to an Xbox console; especially if I gamed on both.
The Windows store is complete mess that's impossible to navigate if you don't already know what you're looking for. The Windows store is the desktop equivalent of a mobile phone marketplace: a ton of pay 2 win freemium games mixed in with a whole lot of "lifestyle" apps you'll never use. And half of them don't even work on PC (!?!?). And mixed in with that junk are actual "real" games like Forza Horizon 3 that you'll have to do a hard search to find.
And I doubt you'll be...