I think MGS4 will be the better game, but it's going to be difficult to get higher ratings than GTAIV got, it got a bunch load of 10's, so hopefully it does too.
GTAIV on 360/ps3 will always outsell it though but if you take into account just the ps3 sales, it should be pretty close.
The fact that it's the last MGS and the first for the ps3 should mean it sells very well.








