It is important to note that the use of DFT methods, larger basis sets, and PCM solvent does result in a greater computational cost. For N-methylacetamide, a molecule that is fairly typical of our benchmark set, the one-electron properties calculations in gas phase using B3LYP/aug-cc-pV(T+d)Z and PW6B95/def2-TZVPD are approximately 22 and 18 times more expensive than HF/6-31G*. The costs go up by approximately an order of magnitude with the use of implicit solvent, but the incorporation of modern domain decomposition approaches for implicit solvation into Psi4 should reduce the cost of implicit solvent calculations to the same order of magnitude as the gas phase calculations. Nonetheless, the development of fast charge assignment methods (i.e., AM1-BCC-type approaches) that have been trained on these higher quality electronic structure methods would also be a useful contribution. In summary, our work leads us to recommend that ab initio charge derivation methods for future MM force fields be based on electronic structure calculations performed using DFT or other affordable post-HF methods, augmented basis sets of good quality, and implicit or explicit solvent that will systematically and reliably overpolarize the molecular charge distribution. It is important to note that any change of the underlying electrostatic model in a force field will require the re-parameterization of the parameters governing van der Waals interactions (e.g., Lennard-Jones parameters). We believe, however, that such efforts will likely be worthwhile in terms of yielding nonbonded parameters that are more transferable because they will not have to compensate for moiety-specific systematic errors in the electrostatic description caused by the inconsistent overpolarization predictions of the sort that we have documented in this work. We hope to further explore the impact of different charge/electrostatic model derivation methods on overall force field accuracy in future work.