Suggested by Sonic Omega Shenron is a being of incredible power. For a while he was the strongest villain in Dragon Ball history. While he no longer holds that title, the guy is still strong enough to defeat Boros. Boros has incredible speed but definitely lacks the raw power that Omega Shenron possesses. In a battle of endurance Boros may have the slight edge with his regeneration but that assumes both fighters are hitting each other equally which will not be the case here. Omega Shenron wins.