both great bands....... having played bass for thirty years..... i'll go with Rush on the pure musicianship part of things..... Led Zep are no slouches .... great voice, guitar, bass and drums........ listened to both forever..... two different styles..... different fan base..... both a 10 on their respective scales....... my opinion.... I like the creativity both bass-wise, guitar-wise, drum-wise and lyric-wise.... so I've got no choice but to throw Rush my vote.......