"If you take some internet forum poster's word, then you've got to take my word that this forum moderator (who have would have no idea regarding porting dev costs -- why would he?) is dead wrong. ;)"
You obviously don't know who I mean. Christian Svensson (his username is Sven) is a vice president of the company. He kind of knows what he's writing.
And if you think about it, porting isn't easy. Take a single texture. Put it from the PS3 to the 360 and you have to rewrite how the GPU generates it, how the VRAM handles it taking into account size, bandwidth, clock speed, and latency, and how the shader pipelines handle it. And do that for every texture in the game.
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs
