Itachi imo. they're tied in the databook and kishi made their deaths insanely similar and close, even down to them one shotting an s-rank (konan and orochimaru), and then choosing to die for the purpose they believed in, within minutes of each other.
itachi has tsukuyomi and amaterasu which can give jiraiya loads of trouble. jiraiya has his bunshin, and large aoe techs which are virtually unescapable and would circumvent susanoo, like swamp of the underworld and goemon, not to mention sage mode.