They're both kage level. I agree on that one, but to say Kakashi's sharingan would overwhelm Jiraiya after some battling. I guess you should follow your own advice and better state your reasons and why. Jiraiya has much more chakra reserves than kakashi has, so it is Kakashi, due to the sharingan's high levels of chakra consumption, the one who would be overwhelm by Jiraiya. Is one smarter than the other? I could not say. What I can say is that experience is on Jiraiya's side, and that weights a lot. Sage mode as used by Jiraiya has no limit of time due to Fukasaku and Shima's fussion with Jiraiya. They constantly mold nature's chakra for Jiraiya to use in battle-by the way Fukasaku mentioned to Naruto that he and Jiraiya were among the few to develop the nature chakra mold training due to their high levels of chakra, this as a reference kakashi would overwhelm Jiraiya-. Kakashi did good against Deva and Asura path. Ok, but . . . he died. Jiraiya died by being ambush by the SIX paths of pain. (Ok! Five). By the way, against those two, Kakashi never had the advantage. Jiraiya took advantage over three paths and killed them.
