  I discuss the standard SVZ-expansion of the QCD two-point correlators in
terms of the QCD vacuum condensates and beyond it due to a new unflavoured
1/Q^2-term (tachyonic gluon mass squared \lambda^2) which modelizes the effects
of uncalculated higher order perturbative terms. The approach is confronted
with low-energy and lattice data. One can notice that, in the different
examples studied here, high-dimension condensates are expected to deviate
largely from their vacuum saturation (large N_c) values, while the new
1/Q^2-term due to \lambda^2 solves the hadronic mass scale hierarchy-puzzle
encountered in the early SVZ-sum rule analysis and improves the low-energy
phenomenology. From tau-decay data, one can extract the running strange quark
mass m_s(2 GeV)=(93^{+29}_{-32}) MeV and a more accurate value of the QCD
coupling \alpha_s(M_Z)=0.117+- 0.002.
