Apparently it was supposed to be a two and a half hour movie, then became six hours because Jackson didn't want to spend just a few minutes on each day, even though some days are boring AF, and literally nothing happens on other days where there's no film or audio.
Plus he wanted the full 40 minutes on the rooftop even though three of the songs are just Get Back, and the most interesting aspect is the reaction and comments from the people below.
Then he was told there wouldn't be an extended DVD (there is no way there won't be tons of different cuts of this), so he threw in another two hours that he'd cut out to get down to six hours. So it became eight.
Unfortunately that means while it's an incredible technical feat - 20 minutes in I had remember this was the actual Beatles and not actors, because they looked and sounded so different from their 'performance' mode in crappy quality video and black and white - and there is some great stuff showing the camaraderie of the guys and they play songs that end up on Abbey Road and their solo albums, lots of people will miss it because they understandably either give up or fast forward/skip.
Because of the 'restoration' involved in this, I watched Jackson's
They Shall Not Grow Old, about front line British soldiers in WWI. On a technical level the 'enhancing' of typical grainy black and white sped up silent footage we usually see from 100 years ago is incredible, and at 90 minutes it's a far easier watch (apart from the trench foot).