  The data on neutrino mixing are at present compatible with Tri-Bimaximal (TB)
mixing. If one takes this indication seriously then the models that lead to TB
mixing in first approximation are particularly interesting and A4 models are
prominent in this list. However, the agreement of TB mixing with the data could
still be an accident. We discuss a recent model based on S4 where Bimaximal
mixing is instead valid at leading order and the large corrections needed to
reproduce the data arise from the diagonalization of charged leptons. The value
of $\theta_{13}$ could distinguish between the two alternatives.
