SBP is physically superior, but can't compete with Darkseid's energy powers. It depends who gets in a good hit first and follows it up. Actually, if we're using SBP after he donned the armor, that actually lowers his chances, since Darkseid's beams could just destroy it or teleport it away, leaving him powerless. Besides, the armor didn't power him up or anything. It just allowed him to retain the power he once had after all that red sunlight had sucked his reserves dry.