Something about The Beatles & Led Zeppelin
They didn't comment on each other that much really. Plant, Bonham and Jones were a part of Paul McCartney's supergroup 'Rockestra' and performed in one of the world's first charity rock concerts with The Concert for Kampuchea in 1979.
John Paul Jones was a part of Paul McCartneys fictional band in the 80's film 'Give My Regards To Broadstreet' (included the McCartney hit 'No More Lonely Nights').
Zep members and Beatles were friends through mutual acquaintances, and would appear at each others' weddings and birthday parties, but they weren't exactly close friends. The respect was evident, but there's not too many actual quotes where they comment on each other in public.
George Harrison was more noted for hanging out with Zep than any other Beatle, that's for certain. At John Bonham's 25th birthday party, it was Harrison who started the debauchery all because he knew the nature of the beast he was about to enter.. so instead of bowing his head and succumbing to what he knew was to come (this WAS John Bonhams party after all...enough said) George decided to take the bull by the horns and get things going. When a photo op. presented itself, Harrison grabbed the top tier of Bonham's birthday cake and heaved it at the guest of honor. Pandemonium ensued with Bonham throwing anyone he could find into the swimming pool, Harrison included. Jimmy Page, who could not swim and was dressed in a truly expensive lavender suit.. gave up and simply walked slowly and gallantly into the pool, fully dressed. It was hilarious.
On another note, it was also George Harrison who is given credit for The Rain Song. He commented to Jimmy that the trouble with Zep is that there's not enough ballads. Jimmy wrote The Rain Song, and some say purposefully added the first 2 chords of Harrison's "Something" as the intro to "The Rain Song". Upon initial listening, one cannot argue with that logic. No doubt it is true.