They are probably the most rhythm & bluesish (in a Yardbirds, not a Beyoncé sense) major hard rock band on earth. Zep had similar influences of course, but diluted things with their esoteric crap, folkie leanings and world music influences. When not being contaminated by outside writers, the boys from Boston stuck to their guns.
When I was a young man, I preferred Kiss to Aerosmith, because I found Kiss more accessible. But even then when I heard their records back to back as I sometimes did, I realized that Aerosmith are musicians while Kiss is an entertaining act. You had to be deaf not to hear that Toys in the Attic was in a different musical league to Dressed to Kill. And much as I like Gene S. as a deliverer of blood, fire, provocative one-liners and old-fashioned melodic bass runs, he sounds outright clumsy in comparison to the rhythmic nuances in Tom Hamilton's playing, he can be one funky white cat!