We discuss three applications of NJL- and PNJL-like models to assess aspects of the QCD phase diagram: First, we study the effect of mesonic correlations on the pressure below and above the finite temperature phase transition within a nonlocal PNJL model beyond the mean-field approximation. Second, we reconstruct the phase boundary of an NJL model from a Taylor expansion of the chiral susceptibility about $mu = 0$ and compare the result with the exact phase boundary. Finally, we demonstrate the realization of the non-standard scenario for the critical surface in a three-flavor PNJL model with a $mu$-dependent determinant interaction.