Very simple at the height of each other's power who was A- Making the most money. B- Exerted more influence over all of LCN. C- Overall the most powerful boss.
Simply put I don't think there was any boss more powerful than Luciano. He had all of the future bosses in his pocket that he was able to control and lead big egos and violent bosses. Carlo's intelligence and cunning I feel like where unmatched but he didn't have the power to do what Luciano was able to do which is why I believe Luciano was the most powerful.
Carlo Gambino died in his own bed in the country of his choosing. Furthermore, to say that Luciano controlled the future bosses is ridiculous. He couldn't even prevent the Costello-Genovese clusterfuck from happening, and that was within his own family. It's an unfair comparison anyway. They were close enough in age, but Gambino didn't attain the lion's share of his power until years after Luciano got jailed and then deported.
That said, I think the Luciano/Costello/Lansky triumvirate was the most intelligent in the history of organized crime. Without their vision, the Italian-American Mafia wouldn't have seen a second generation, let alone last a hundred years.
