I actually booked the tour for my wife who is a huge Beatles fan (I was in Liverpool for the football) but it happened to be much more interesting that I expected. In 1,5 hours I learned a lot about the Fab4 and the city. Our guide Jean was very knowledgeable and her presentation was very interesting. She tells you the little interesting facts that are not always included in the touristic guide books and was always happy to answer the questions we had. During the tour you get to see and learn about the Liverpool Docks, the Fab4 statue at the waterfront, the "Double Fantasy" John Lennon & Yoko Ono exhibition in the Museum of Liverpool (very impressive), the Cathedral of Liverpool (but not part of the walk) and of course Matthew street and the Cavern club where it all began.
It's definitely a must when visiting Liverpool.
One more time - Thank you, Jean !