  Solar neutrino experiments have yet to see directly the transition region
between matter-enhanced and vacuum oscillations. The transition region is
particularly sensitive to models of non-standard neutrino interactions and
propagation. We examine several such non-standard models, which predict a
lower-energy transition region and a flatter survival probability for the ^{8}B
solar neutrinos than the standard large-mixing angle (LMA) model. We find that
while some of the non-standard models provide a better fit to the solar
neutrino data set, the large measured value of \theta_{13} and the size of the
experimental uncertainties lead to a low statistical significance for these
fits. We have also examined whether simple changes to the solar density profile
can lead to a flatter ^{8}B survival probability than the LMA prediction, but
find that this is not the case for reasonable changes. We conclude that the
data in this critical region is still too poor to determine whether any of
these models, or LMA, is the best description of the data.
