Regarding the Gears II to Killzone II comparison... The difference is that we don't have the same offerings coming from Microsoft than from Sony. They decided to kill most of their first party studios, and they don't spend the same time or money than Sony does, so we don't really know what the X360 is capable of in the technological point of view. Comparing a game made with the Unreal Engine 3 to a game with a custom made engine, with much more budget and time of development, is not the best way to check what are capable of the respective consoles. The Forza 3 - GT5 will be a fairer comparison, taking into consideration the different budgets and time of development.
It's a marketing decision made by Sony, they decided to spend a lot of money in internal studios that make great technological demos (and some of them are great games at the same time) Microsoft decided to give to the third party studios more room to breathe, leaving them more market share and more earnings. Different decisions that give you different results, and in this generation, better 3rd party suport to the XBox360.







