The final set contains 16 barrier heights and 39 reaction energies, for a total of 55 data points, and was used to test a range of density functionals across the top four rungs of Jacob's Ladder (GGAs up to double hybrids). SOS0-PBE0-2-D3(BJ) had the lowest MAD of all functionals, while ωB97M-V was the best hybrid functional; we also recommend revDOD-PBEP86-D4 and ωB97X-V based on an analysis of MAPDs across the whole set and then each enzyme individually. SOS0-PBE0-2 and revDOD-PBEP86-D4 are both spinopposite-scaled double hybrids, and our results reaffirm previous studies which show that SCS-MP2 and SOS-MP2 are significantly better for transition metals than standard MP2. We also recommend PBE0-DH specifically for copper-dependent enzymes, which are more sensitive to the amount of MP2 correlation in double hybrid DFAs. B3LYP, despite its popularity in metalloenzyme modeling, is clearly outperformed by multiple other hybrids, even in its best dispersion-corrected form [B3LYP-D3(BJ))]. Tests of three different basis sets showed that def2-TZVPP gives almost identical results to def2-QZVPP, but double-ζ basis sets are insufficiently small.