Marciano by a shade,his old challengers were not as old nor were they inactive like most of Jeffries.
With how people talk about Marciano I think Kimbo Slice had a better career in the backyards of Florida.
Era for era Jeffries. In terms of whose competition was more difficult its clearly Marciano. It doesn't matter what version of Louis, Charles, Moore and Walcott Marciano was facing they Rex Layne and LaStarza would run through Jeffries competition while seldom losing a round. Guys like Cockell, Matthews, Savold, Reynolds etc would all be champion in 1900. Fitz is the only one of Jeffries title opponents who could beat Marcianos top 10 or so opponents. Armstrong might have some success because hes 6 ft 4. The rest get destroyed.
