User blog comment:Legionaire22/Primarch Feats of Strength/@comment-4966170-20130702112846/@comment-3258762-20130702115402

Horus himself spoke against that. He said himself that out of all the Primarchs, only Guilliman could best him in the strategic parts of war. Horus, however, was much better at recognizing and utilizing other Legions strengths and weaknesses, but one on one, Guilliman was better, if only a little bit.