Overall, the picture that emerges from these data are that the somewhat larger errors for hydrogenbonded complexes that were documented for S66 dimers when the 6-311++G(3df,2pd) basis set is used (MAE of 1.0 kcal/mol and maximum error of 4.4 kcal/mol, whereas the maximum error for def2-TZVPD is 0.5 kcal/mol) result primarily from inadequate description of exchange rather than electrostatics or induction. The def2-TZVPD basis set offers reasonably consistent performance for each energy component, with errors that are 1.5 kcal/mol in each.