Oliver Twist is one of Dickens' early novels - he worked on The Pickwick Papers, Oliver Twist and Nicholas Nickleby simultaneously - and one of his best loved. It has what you would expect from him: memorable characters, evocative descriptions, melodrama, pathos (more often bathos) and a plot that relies on completely incredible coincidences. These latter are sometimes explained away by the characters themselves as being ordained by Fate, benign or otherwise, and must have been more acceptable to a Victorian readership than to one of the present day, who are likely to groan at each 'who should it be but' revelation.
The crossovers with Pickwick and Nickleby are noticeable. For example, The Artful's court appearance is clearly intended to be as funny as Sam Weller's, although it pales by comparison.
The most famous character is of course Fagin, and Dickens' casual anti-Semitism in his treatment of him is another thing that might discomfit the modern reader. He references him as The Jew, always in a derogatory manner. That this is a reflection of contemporary attitudes can be seen from Scott's Ivanhoe, in which Jewish characters are treated with similar hostility and contempt. But it is not the main characters that are most successful - and especially not the title character himself, who is innocent and bland beyond belief - but the supporting cast; Mr. Bumble and his lady, the servants in the house that gets burgled, the old bachelor who keeps threatening to eat his own head, and many others. They make the book a delight.
As always, Dickens is the master of descriptive narrative and he conjures a grim and compelling view of Victorian London's underside.
If you have not yet read any Dickens, this is not a bad book with which to start, although for younger readers (teens) I would recommend Hard Times as their first. Either book will probably leave you, like Oliver, wanting more.