Again, I'm a biased person, but I'd say go for Revs. I think it's a fabulous subject! A few marks dropped in further can really be costly, and it's a marked down subject, which is not the case for Revs. And - I see that you're doing UMEP History, which I've heard is basically about Revolutions. So think about it this way - UMEP History+VCE Revs=1.5 subjects

You'll get a decent overlap, but not enough to make you bored of it. So in effect, by doing your reading for one of those subjects, you've already done a lot of reading for the other, which saves you a good amount of time. I'm in the same situation, but with different subjects - I'm doing VCE English Language, but I'm also taking UMEP Linguistics, and I'm finding that they really complement each other nicely, having been through a whole semester already. Hope that helps somewhat
