In my opinion, the they both look fantastic. It's very difficult for me to choose which one is the best because they're both are awesome looking cars. While the Zonda fits and looks good in all colours and schemes, the Huayra doesn't. So far, the only colour that I think suits the Huayra better is red just like the one posted by ExigeEvan. The beige colour like posted by the OP ruins the whole car that it looks awkward.
Therefore, if I really have to choose one I'd go with the Zonda. Of course, my opinion only.