Well, the look changer is in the core version, but my understanding is that the macOS look is only available in the paid versions, as well as a few other looks. As for Zorin background plus, you can get an idea of what it looks with this video.
http://www.youtube.com/watch?v=Coiae3Erhjk&feature=player_embeddedI've seen videos of people using something similar on their computers (namely green characters moving on a black background matrix style) but this seems to be an easier and more flexible way of going about it.
At any rate, if you're going to try the core version you should probably consider looking into the live session ( I personally found it faster than fedora 15 and the enlightment version of the latest pclinuxOS)
As a final note, I'd like to point out that there are some relatively important weaknesses to ZorinOS, even if they are understandable and the developers aren't at fault. The most important one, to me, would be that at some point the user will have to leave his or her comfort zone to stay up to date. for instance, the repos are not updated. The same goes for upgrades, as they are tied to Ubuntu and thus a wrong click could potentially ruin your machine (as evidenced by the warning not to upgrade zorin 4 to Ubuntu 11.04). These two things could be solved in the future by the dev team if they ever manage to create their own upgrade path and it might even represent a chance to monetize the OS further, but I don't see that happening in the near future.