The list definitely imo looks better on Microsoft, they've been able to get their biggest games to reach out further then Sony has. I'd assume it's just them having a clearer vision on how to market these things. It'll be interesting to see how UC3 and Gears 3 compare this holiday... imo theres no reason why UC3 should sell less then gears... but it probably will, cause Sony can't market it like MS.
I would assume the list is going to go more towards a Sony lead in the future too? Simply cause they're releasing more games then MS... On the other hand Gears 3 and Kinect Sports 2 (and their other Kinect games) will probably outsell all of Sony's remaining line up this year lol.