Zep put out two great studio albums, both dominated by Jon Bonham...#1 and Physical Graffitti. The rest of their albums span from mediocre to lousy.
I saw them twice live.
The sucked both times, and I mean sucked.
Saw both Sabbath and Floyd live twice too. Both times they both burned the house down, leaving all who attended simply stunned with wonderment.
I saw Sabbath also at Live Aid (they were on earlier vs Zeppelin in Philadelphia) and on the 13 tour and they were pretty solid. I wasn't stunned by Sabbath but they held their own (the Scorpions were better when I saw them a few years earlier, as was Judas Priest last year).
The closest I got to seeing Floyd was Roger Waters' Wall Tour, which was the best multimedia extravaganza I ever saw...of course with his mask off and he's gone full anti-Semite I am boycotting him. I'd love to see David Gilmour.