Fact of the matter is this, despite the following:
1) Starting with a very high price tag
2) Coming to the market a year later than it's competitors
3) Costing more than the Xbox 360 for it's entire time on the market
4) Receiving the lesser quality version of games in almost all cross platform titles
5) Having a lower fault rate (less people forced to purchase new machines)
6) Having very few decent games for it's first two years on the market
7) Being virtually hated by most media, news and gaming news outlets across the US for first year to the market
8) Launching in a less stable economical climate
Despite all of that, it's clear that the PlayStation 3 will fairly soon overtake the Xbox 360 in both shipped and sold units.
Despite all of that, if you shift the launch dates so they match, and compare units sold, side by side over the same time frame, the Xbox 360 has always been behind in worldwide sales, with the gap growing each year.
Sure you can say "buhu, but the ps3 is still behind", and technically you'll be right, but then you have to realize that less than 2 million units ahead in a full year more on sale, isn't anything to be gloating about.