It's true that half the film deals with the Beatles years, which has been covered so often, but there's plenty of footage I've never seen before (and I've seen a LOT of Beatles footage). It also shows Harrison's solo career (including the Traveling Wilburys), spirituality, passion for auto racing and film making (including Monty Python), and his family.
Even though it's 3-4 hours, it could easily have been longer. It's not a proper biography in that it doesn't fill in the gaps between periods of time and it assumes you already know much of his history... if you do, the film works well and shows much new footage. I think the film works, in that it captures the essence of Harrison as a person.
Many could argue that the reason we know George is because of the music, and so the film should have far more footage of him performing and recording (for example, a clip of Harrison performing on Saturday Night Live in the late 1970's, or during his Japan tour in 1991, or include some of his unique music videos), stress each of his solo hits (for example, Blow Away, All Those Years Ago, the hits from the Cloud Nine album, etc.), and have far less talking about his film making, auto racing, etc.
Overall, at around $20 I think this film offers much bang for your buck. I also think George deserves to have a comprehensive DVD release of all his videos and concerts.