I like the open approach to their R&D of this controller. I think they have put more thought into the evolution of standard pads than a lot of people, whereas the Xbox and PlayStation have to stick to their 'brand'.
We all know its a compromise. It's not there to replace or compete with a mouse and keyboard, and twin-sticks are likely always going to be better for games made for them. What this offers is that ability to play 'PC games' on the couch, for the living room experience that SteamOS is standing for. The ability to play games never intended for controllers. The grand strategies, the point and click adventures or city building games.
However, if they can make a pad that is quick and accurate enough to be half way competitive on DOTA2, they'll be on for a winner.