I agree defensive play is more effective here than at IYT. It is easier to gain complete information which, in turn, makes material relatively more important (and initiative less important).
It's hard to judge how effective one style is compared to another. Though I think a defensive style is technically better, I doubt it makes a huge difference and I think most players prefer an aggressive style.
I consider myself relatively aggressive, but of the 2000+ rated players I am familiar with only Mark and dAGGER are clearly more defensive than I am. On the other hand, only pcron and Borg-one were clearly more aggressive. The rest seem willing to gamble some of the time . . . a poker analogy is probably appropriate here.