Tangent: In addition to that, I think this generation might be defined by how well each console opens up to smaller/indie developers.
Modern day indie developers are making products which we would have called AAA games in 1998 and many of them are selling extremely well (just see Kickstarter). I think they have a HUGE role to play this generation, and holding them hostage in the "app" sandbox will be a massive mistake.
If either Microsoft or Sony opened up their SDK to indie developers, and created some kind of arrangement where these developers could sell digitally for a fee, I think they will effectively "win" this round. And I do not mean "apps." I mean full power of the console level stuff.