I finished Oliver Twist a day or so ago, and thought I'd post a few thoughts here. This thread is all about ranking Dickens major novels, and I'm not sure where I would put Twist. Its both fantastic and relatively poor, in almost equal degree, and given the contrasting merits of that duality, I'd better add a few remarks.
Twist is an early novel (Dickens was about 25 when he wrote it) and this probably underlies the weaknesses. It's perhaps overly melodramatic, and others have commented on this for over a hundred years, but that's not my main problem with the book. In fact, I like my Dickens to be melodramatic. The problems stem principally from the plot of Oliver's parentage and life story. This is weakly done, poorly explained, full of ludicrous coincidence, and centers on a relatively unengaging character (Twist himself). The positives are everything else. Outside of the weak underlying story arc, we have scenes involving the criminals in the book that are entirely fantastic. Bill Sikes is superbly drawn - bad to the core and a ruined man, and the chapters involving him are solid gold. Every time Sikes enters the story the novel crackles with energy. The robbery, murder and rooftop escape scenes are unforgettable. While Sikes is corrupt and violent, Fagin is a portrait of evil and is engagingly drawn. If Dickens had written a novel centering on these characters and less on the perfect lad and his highly unlikely backstory I feel it would be a better book. Chesterton wrote that Oliver Twist "is not of great value, but it is of great importance". Its hard not to agree. However, it is what it is - a relatively weak novel with many wonderful scenes. That said, its mostly quite pacey and not too long, so I would recommend it. I had to remind myself it was written by a young man, 180 years ago. It is quite a literary achievement, even if its not his best.
So how to rank it? Based on memorable scenes, its right at the very top; overall as a cohesive novel, much lower. I think my ranking has to now come out like this:
Bleak House
Great Expectations
Dombey and Son
David Copperfield*
Oliver Twist
(* poorly remembered compared to the others, to be fair; I read it over 30 years ago)
Now what Dickens to read next? A late novel I suspect, but I'm taking a break and reading some SF and detective stuff for a bit. I still hope to knock off 2-3 more Dickens this year though.