Physical Graffiti is self-indulgent but nicely varied. A lot of the material on it is less pretentious than the usual Zep fare. I remember the Rolling Stone review, they clobbered Kashmir as "boring after the first two minutes". My favorite Zep album along with the unavoidable IV - though that contains Stay away from Heaven or whatever it is called, from the first listen I thought that song a pretentious amalgam of hot air.
True Coverdale, even before he became blond Daisy, is more Plant than Gillan, also harder to understand than Gillan! Plant and Coverdale both have strong blues influences, Gillan was more a Elvis Presley and Little Richard buff. Of course, Gillan can wipe the foor with both of them as a lyricist.
