  We present a detailed comparison of the most recent sets of NNLO PDFs from
the ABM, CT, HERAPDF, MSTW and NNPDF collaborations. We compare parton
distributions at low and high scales and parton luminosities relevant for LHC
phenomenology. We study the PDF dependence of LHC benchmark inclusive cross
sections and differential distributions for electroweak boson and jet
production in the cases in which the experimental covariance matrix is
available. We quantify the agreement between data and theory by computing the
chi2 for each data set with all the various PDFs. PDF comparisons are performed
consistently for common values of the strong coupling. We also present a
benchmark comparison of jet production at the LHC, comparing the results from
various available codes and scale settings. Finally, we discuss the
implications of the updated NNLO PDF sets for the combined PDF+alphaS
uncertainty in the gluon fusion Higgs production cross section.
