I was a bit skeptical to think the responsiveness of the UI would be as fast as we've seen. But wow, after seeing this AND it being just a devkit. . . I'm impressed.
However they could have shown something more useful than IE
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I'm buying an XB1 as a tool for Indie Development, but I can't deny how much I'm going to love the easy-to-use interface. Voice commands this complex look like a gimmick that actually seems useful, but I honestly see myself disconnecting the Kinect so I'm not constantly accidentally turning my Xbox on when talking about Xbox over PC chat or something.