  We perform a complete global phenomenological analysis of a realistic
string-inspired model based on the supersymmetric Pati-Salam $SU(4)\times
SU(2)_L \times SU(2)_R$ gauge group supplemented by a U(1) family symmetry, and
present predictions for all observables including muon $g-2$, $\tau \to \mu
\gamma$, and the CHOOZ angle. Our analysis demonstrates the compatibility of
such a model with all laboratory data including charged fermion masses and
mixing angles, LMA MSW and atmospheric neutrino masses and mixing angles, and
$b \to s \gamma$, allowing for small deviations from third family Yukawa
unification. We show that in such models the squark and slepton masses may be
rather light compared to similar models with exact Yukawa unification.
