Luffy beat Kaido, so he is stronger than Kaido. Oda has always been straightforward with Luffy's powerlevels, no point in analyzing stats.
But its gonna be fucking hilarious when Luffy gets his ass beaten by somebody (Admirals/Giants/Weevil who knows) and then people have to come to term with the fact that Kaido isn't all that he is cracked up to be.