If it comes with Big Picture, it's a no for me (for a while ). If I can do almost the same by plugging my PC to a TV...
I'd be happier if they announced a Steam Controller, to be honest.
But you can configure Steam to start without Big Picture. It'll open the default Windows / Ubuntu interface.
Pro: it won't become a resource hog
Con: You probably won't be able to use a controller to browse through the interface, so a mouse will be mandatory.