Brains, for sure. Beauty can get you far, but only for so long. Everybody gets old and ugly. Brains can get your further for a long time, but how you use them is also important.
This is a very good question. I'm working on a HUGE Bratz project at bratzpack.fandom.com. More Bratz videos will be uploaded to my channel for the Bratz's 20th Anniversary, so stay tuned!