  Recently SO(10) models with type-II see-saw dominance have been proposed as a
promising framework for obtaining Grand Unification theories with approximate
Tri-bimaximal (TB) mixing in the neutrino sector. We make a general study of
SO(10) models with type-II see-saw dominance and show that an excellent fit can
be obtained for fermion masses and mixings, also including the neutrino sector.
To make this statement more significant we compare the performance of type-II
see-saw dominance models in fitting the fermion masses and mixings with more
conventional models which have no built-in TB mixing in the neutrino sector.
For a fair comparison the same input data and fitting procedure is adopted for
all different theories. We find that the type-II dominance models lead to an
excellent fit, comparable with the best among the available models, but the
tight structure of this framework implies a significantly larger amount of fine
tuning with respect to other approaches.
