Too soon to say IMO. How it affects the console market will likely have to do with price and ease of use. Being really powerful isn't going to make a difference if it's too pricey for the masses; it can't be much higher than the $500 X1 if it wants to succeed here. Also, they need to eliminate as many of the typical PC hoops as possible so that the average Joe can easily set it up and play the games without needing to tweak stuff to make it work.
The PC market is a bit different; the cost and the set-up won't be a problem, but will PC gamers feel the need to buy new hardware and switch operating systems? How good is Steam OS in running all the other programs that PC gamers use their computers for?
Finally, the controller is a question mark for both markets. It seems like a very versatile controller, but it runs the risk of being OK at many things, but not great in any. PC gamers might like it better than Xbox controllers for playing shooters, but would they rather just stick with KB/M? And how well does it work for hack-n-slash games, or fighting games? We'll probably just need hands-on time to answer those questions.
