We present the comparisons of two independent Monte Carlo event generators,
HORACE and WINHAC, for single-W-boson production in hadronic collisions with
multiphoton effects in leptonic W decays. These comparisons were performed
first at the parton level with fixed quark-beams energy, and then at the hadron
level for proton-proton collisions at the LHC. In general, a good agreement
between the two programs has been found. Possible sources of differences in
some of the presented results are discussed. We also present and discuss the
effects of including non-zero quark masses for the main single-W-boson
observables at the LHC.Comment: 32 pages, 40 PostScript figure
