I just bought an Xbox One, and so far I'm very underwhelmed. The interface is a hassle to navigate, with everything hidden away inside apps. The Xbox Store is a mess, with no way to sort products by price, publisher, release date, etc. You can't rate or comment on gameplay clips made with the Upload Studio. And I hate how you can't swap out the hard drive like you can on the PS4.
PS4's interface is much cleaner and better organized. All the important settings are at the top of the screen. The social features are implemented better, with Facebook, Twitch, and Ustream built into the system OS. The Share button makes uploading and broadcasting gameplay clips incredibly easy, and I'm surprised that the Xbox One doesn't have one.
And what's with all this talk of Microsoft giving up on the Xbox brand? It's their most popular product next to Windows. Xbox has proven to be successful, if Microsoft dumps it then I'll definitely switch to PS4.
Speaking of Windows, it's had many failures, but MS never gave up on it. The failure of Windows 2000 led to XP, Vista led to Windows 7, etc.