Led Zeppelin used to be my favorite band, but I got over them and moved on to U2 in college. I love them, but for my money, technical skill and complexity doesn't matter nearly as much as emotional expression and atmosphere. U2 are better at the latter two, better at them than any other band imo.
Led Zeppelin also has a tendency to be a little bit masturbatory. They have a song that jokes about the bridge never coming and that was designed to be undanceable but was named like a dance song. Funny for a bit, then the joke wears off quick and you are left with nothing of value.
That said, Led Zep IV is a masterpiece. Levee Breaks alone is just ridiculously great.