It has, I believe, exceeded all my hopes. Evelina was written in the 1770s, and in the beginning I had to keep reminding myself of this, because all my Jane Austen associations were so overpowering. As I got further into the book, however, these associations receded--not because they ceased to be true, but because the book was so good I never thought of anything but the present story.
The easy explanation of the plot is this: Evelina is the heroine, a naive but good and intelligent young girl, raised wholly in the country, who goes to London for the first time and embarrasses herself a lot. Because Evelina is so ignorant of town customs, she's the perfect person to point out their absurdities, and in this way the book is social commentary. There's also a question of her parentage, because her father is a cad who left her mother and claimed they weren't married, and the story surrounding this, when it is finally solved, sounds very much like something out of a play, full of misunderstandings. And of course, there is a love story.
I have never read anything written prior to Jane Austen, aside from poetry and Shakespeare, so I was not entirely sure what to expect from this. The novel is written in letters. I was surprised by how often the language sounded like Shakespeare, despite being written almost 200 years later. Certain phrases and modes of wit we associate with Shakespeare turned up here, none of which I've ever noticed in Jane Austen, 40 years later. Perhaps this is partly to do with Burney's writing style, or her choice of characters, or simply 40 years of language change.
I found Evelina captivating, though I couldn't quite tell you why. It has a certain quality, in common with Elizabeth Gaskell novels despite myriad differences between the two writers, which makes it thoroughly satisfying. I loved it.