Sathor - afaik, it doesn't matter what scale you compile at, it seems to produce the same result each time, though I haven't experimented with this enough to be honest, Apparently according to Tay, this isn't TRUE AO, it's some sort of advanced radiosity baking computation (or some shit) which also exists in the ASW engine. The AO-looking output is a 'side effect' of this new feature. I'm guessing 1/4 life or MrTwo know more about this than me, so I'll find out exactly what is up.
Will_B - Sure. I'll upload some pics once I'm back from London this evening! Also thanks for the kind words!
joe_rogers - You see the smooth shadowing/shading that appears on brush edges and corners? That's what this 'AO' does to brushes. You don't get these quite vulgar flat looking sides of geometry that intersect, and it gives scenes a greater sense of depth IMO.
Again I'll get some comparison shots up when I'm home, unless someone beats me to it