@BryonyRae I asked that particular question too. ;) SimGuruLeanne wasn't allowed to spill the beans though beyond subjectivity being a part of it which is understandable. They do seem to be doing well in choosing a variety of builds with varying amounts of elements (architecture, landscaping, interior design (for rooms especially), use of objects and lighting/color) so we don't always see the same theme or skill level being favorited. I don't think a lot of us on the forums here have anything to worry about, I'm thinking disaster (MOOed stuff ending up in strange places, areas that are furnished but routing is blocked) or CC would prevent a favorite. Some of the MOO issues we can't really do much about, or like Cerrydd pointed out that not every lot yields the same placement results.
EA Staff (Retired)