Comment on Perez et al [PRX 2, 041005 (2012), arXiv:1209.2011]
  Recently Perez et al [arXiv:1209.2011] wrote on the spectral slope of MHD
turbulence claiming that it is consistent with -3/2. This work contains a
number of errors, factual inaccuracies and puzzling methods in the
interpretation of numerics. We argue that the numerical evidence that the
authors presented is actually against -3/2 slope and the assumption of
universal alignment, opposite to what they claim. Perhaps the most puzzling is
the Fig.8 that claims that the authors measured the inertial range length and
that it is consistent with Re^2/3 scaling. At a close inspection it appears
that the datapoints are not the result of a measurement, but rather were
calculated by a formula.
