  Shell model calculations with the neutron effective charge as single free
parameter describe well the \bet and \bef rates for $N\le 64$ in the Cd and Sn
isotopes. The former exhibit weak permanent deformation corroborating the
prediction of a pseudo SU3 symmetry, which remains of heuristic value in the
latter, though the pairing force erodes the quadrupole dominance. Calculations
in $10^7$ and $10^{10}$-dimensional spaces exhibit almost identical patterns: A
vindication of the shell model. For $N\ge 64$ quadrupole dominance is
accentuated in the Cd isotopes and gives way to seniority dominance for the Sn
isotopes.
