This movie deserves no less than a 5 because it is simply THE MOST AMAZING ANIMATED FILM ever made.
And I put the blame entirely on the deadly duo of Miyazaki and Studio Ghibli. Miyazaki once mentioned about the concept of emptiness or "ma." These are the seemingly empty moments in between frames, when nothing of consequence happens but the plot advances and you feel sated. In an interview, Miyazaki mentioned that as a filmmaker, he firmly believed in "ma". It is what other film makers shy away from - in a bid to keep their audience engaged. And it s this what Miyazaki's films are full of, and leave you feel no less sated.
A visual treat, every frame is taken care of and you can see Miyazaki reward his fans with allusions to previous works. The small soot balls, the lamp-post-cum-lantern that guides the way, Yubaba's ginormous child and the talking heads are all unnecessary to the plot, yet they are what makes the film memorable. The bathhouse with it's elaborate decorations, Sen's slow descent down the stairs to the furnace - these are the frames that are etched in one's mind forever. There is also a stress on grey characters - Chihiro is both sacrificing and selfish, Haku is both loving and deceitful, No-face is both - Sen's protector and a glutton. Much like real life. There is also metaphors aplenty! We see Chihiro's parents turn into pigs due to their gluttony of "wolfing like a pig".
This is a film for both adults and children alike because each age group will find a new layer to it. Miyazaki once mentioned that the entire film was simply a metaphor for the Japanese adult film industry and while there have been heavy debates both for and against this topic, I implore you to watch this film for it's richness in dialogue, ma and animation.