I don't see any differences at all between a villa and a casa, features-wise. You don't seem to get anymore for the extra 7,000 sestercii except the swank value of knowing you paid more for it LOL. The only differences I see are between patron and citizen - a patron can post articles and threads to their discussion boards, we citizens can't (it's weird though that we can create the discussion board but not start an actual thread on it...!)