I really can't judge on this one seeing how I have neither a 360 or a PS3.
But what I am going to say is this.
My money's going with the PS3.
Sony announced Sunday that they will not be releasing it next month.. but rather November.
This gives them time to work out the bugs in the system, distribute enough systems so people can get them, and it will be like $200 cheaper than the anticipated price.. while Microsoft did none of these for 360 except for the crappy 'no hard-drive' system.
Plus I'm one of those Anti-Xbox - Pro PS2 guys.
MGS4 will own.