It was great. It traced the origins of the band, including all the studio / side projects and previous bands each member was in. I honestly didn't realize how many non-Zeppelin zeitgeist songs Page has played on. The movie looked a bit at their influences, then traced their path through recording and touring their first 2 albums. I'm in for the sequel if they ever make it.
TBH I didn't know much about their origin story, so it filled in plenty of gaps for me. There's some interesting audio interview clips w John Bonham that really completed the story. The video editing was overall good, and while they employed some pretty transparent "tricks of the trade", it was overall really effective.
The imax audio was stellar.