This has been one of my favorite Newbery winners since I was first forced to read it in the sixth grade. I still love it, though looking at it with a more critical eye I see small flaws here and there.
The characters are mostly very well drawn. Kit as the impetuous girl, Matthew her stern and fierce uncle made harder by a hard life, her once-beautiful aunt greyed by the loss of her sons and a lifetime of hard work. The one exception is Mercy. As a child I loved the kind and patient Mercy, but as an adult I find her too one-dimensional. Whereas all of the other characters are complex, complicated people, Mercy is only ever kind and patient to a fault. She fits very clearly into the trope of the handicapped child as an inspiration of patience and gentleness.
The plot is excellently handled. Having recently read a (non-Newbery) book that suffered from too little to keep the characters truly busy, I was all the more primed to appreciate the interweaving of the threads of narrative here. There is the section dealing with politics and charter, the romances of the three girls, and Kit’s friendship with Hannah, all fitting within the larger story of Kit looking for a place to belong. Each of these plot threads interweave with one another, so that the young men courting the girls are involved in the politics, for example. There were a few brief moments where the plot hinged on coincidence (the arrival of the Dolphin towards the end of the story, for instance) but I am willing to forgive these, and apparently so was the 1959 Newbery committee.