Bonzo never talked as much bullshit as Lars for one thing.
But it's really a moot subject, Zep's status was a making of its time, Metallica status is of another era.
But in the narrowness of their musical output, I find Metallica closer to Black Sabbath than to Led Zep. For me, Led Zep transcend categories such as heavy metal and even hard rock.
Metallica is a heavy metal band, even with eye liner and short hair, an influential one in the genre and even one that broke into the market outside of heavy metal, but they are still a heavy metal band. Nothing wrong with that, but it's nothing that can be equated with Zep's eclectic legacy.
See, Rob, I can even write nice things about that band with the aloof hippie singer, the sloppy lead guitarist, the dragging behind drummer and that bass player that was so often buried in the mix. (Quote of Gene Simmons: "With Led Zeppelin, you could never hear the bass proberly." My feelings exactly, I found JPJ's playing largely unobstrusive or maybe the myriad Jimmy Page guitar tracks and Bozo's drum sound left him no room to breathe.)