  In this comment we explain the discrepancy found between the results in
arXiv:0712.1716v1 for the 3PN spin-spin potential and those previously derived
in gr-qc/0604099. We point out that to compare one must include sub-leading
lower order spin-orbit effects which contribute to the spin-spin potential once
one transforms to the PN frame. When these effects are included the results in
arXiv:0712.1716v1 do indeed reproduce those found in gr-qc/0604099.
