Well Playstation is still bigger brand then Xbox, and that is the biggest factor, people while looking for new console might be directed by their previous systems like PS2. Also PS3 is heavily marketed.
Better lineup of games also helps, year ago there was not many good titles on the PS3. Now there is MGS4 and GTA IV for example, it's still not as much as on X360 but it's getting better.
360 is very unreliable, knowing about RROD many people don't want to buy this console, some of them dont have a clue about MS 3 year warranty.
I think blu ray has some impact, but not as big as some people think, Blu ray is still a minor thing compared to normal DVD.
But in conclusion, MS are still doing great, i mean no one expected that they will be 5 milion ahead in this generation going into year 2009. They are establishing their brand, and getting fans and developers behind the console. PS3 still has a lot to do to get to 2nd place. Because Wii is beyond range of HD consoles.
