I've now read D.C. three times and it gets better every time. It was apparently his own favourite book and certainly seems to draw heavily on his own past at times. But ... there's always a point, just after the first half of the book, when it loses its initial momentum and brilliance - basically as David starts to grow up and become an adult. And at times it lapses into the mushy sentiment and melodrama that is always a bit of a mountain to climb for modern readers. In other words, it's at its best when David is a child, and the vulnerability that Dickens must have experienced so painfully himself, is always present. But there's always such a wonderful parade of characters throughout the book: Betsy Trotwood is one of the best female characters throughout his novels (and one of the few convincing ones to my mind) with her fear of intruding donkeys and blunt ways, and the sympathetically drawn mentally-fragile Mr Dick. The Micawbers, of course, and 'umble' Uriah Heap, who has to be one of the most loathsome villains in the history of fiction, and then there's the terrifying Murdstones, who never get the come-uppance you feel they deserve.
Although the narrator is the adult looking back, one feels that he never loses the boy he describes so well, and that I'm sure is probably true of Dickens, who unlike most adults, retained that inner child to an unusual degree. The caricatures that are such a hallmark of Dickens style, singling out oddities and building on them to create characters, is straight out of a child's mind, and never does he do it better than here.