happy hermit:
That may be true. I guess I would have to compare my games against defensive players to those against aggressive players. I will concede that at BK defensive play is more effective than at IYT in the corresponding variations due to move tracking.
As far as space is concerned, an aggressive player tends to acquire space for manuevering while the defensive player may end up with very little space for the same. At least that has been my experience.
It could also be that a less skilled/experienced player may do better playing defensively than aggressively. For me though, I don't want to wait for my opponent to make a mistake but would rather attempt to manuever into a superior position from which to attack.