If the question is who's the best chief of an engineering crew, I'd like to say Geordi, as his was probably the biggest crew, & he does eventually become a starship captain, which one might assume pushes him ahead of Scotty, but Scotty was 3rd in command of the original Enterprise WHILE the chief engineer. I actually think he's probably got an edge on knowing how to lead a crew, & by the time he's old enough to have opted for his own command like LaForge did, he was old enough to realize that wasn't his place in the universe, which means he's probably wiser than all the others too. Nothing wiser than a man who knows that right where he is, is right where he's supposed to be. Hell, even Kirk fumbled about with that. Geordi too... & O'Brien, come to think of it.