The Relativistic Heavy-Ion program has shown that a key property of the Quark-Gluon Plasma (QGP) is its very low shear viscosity to density entropy ratio η/s(T). A key observable is supplied by the different anisotropies the collective flows measured by v_n =. We present a Boltzmann-like transport approach that fixes with η/s(T) the macroscopic dissipation. Such an approach is able to naturally describe the v_n(pT) in a wide range of pT and η/s(T), but also investigate the equilibration and isotropization time scales. Furthermore it allows to study the impact of initial non-equilibrium distribution that can potentially affect the estimate of the QGP viscosity. Finally we will show that in the low p_T region the phase space has large occupation number that could even lead to the onset of a Bose-Einstein condensate.