Although ridiculous as a way of comparison, it is impossible to imagine either one without facial hair. They both have had beards for so long that it has become part of their image. DRAW.
Jaws and Star Wars were the two films that firmly established the blockbuster, changed marketing and the entire distribution system, and effectively demolished the New Hollywood Renaissance (1965-1977). So really you could go with either one, dependent on your preference. Jaws may be a big budget update of the fantastic Duel, but it's just too damn good to criticize!
Further reflection: Spielberg's beard is pedestrian, and just enough to reflect his thoughtful nostalgic tone. Lucas has the beard that represents moody probing thoughts. His THX and Star Wars beard is a masterpiece of this brooding, shy, and thought-provoking style. The later one works, but seems to be there. Nowadays it is really just laughable. Spielberg at least maintains his beard presence.