I think one reason may be that the Play Station brand itself was more established at this point, as we already had two previous consoles of the sort released prior to the PS3's debut. read more
Early on, it may have been that the Xbox 360 was less reliable than the PS3, what with the red ring of death and everything. After that, Microsoft started to close the gap and the sales are just about even now. read more
the xbox 360 sold over 8 million more. I personally prefer this. The PS3 has sold 48 million plus and the Xbox 360 has sold 50 Million. read more
The PS3 has sold more than the 360 once you factor in the 1 year lead that the 360 has and factor in that the 360 has had a longer time at a reduced price (because of the 1 year lead and thus earlier price drop). read more