The premise is a world of gaslamp fantasy, which is like steampunk with a zany twist of mad science and otherworldliness. The main character is Agatha, a girl who is an assistant at a lab for mad scientists, aka Sparks. There are a lot of minor characters and I find that they are all rather unique.
I find it hard not to compare the novel to the graphic novels, upon which it is based. However, I will say that it does stand alone, so there really is no need to compare and contrast. There is a lot of contrast though, and it shows that a cartoon, or comic, is really only a way to tell a story, and that story can be transposed to another medium successfully.
The language is very good; it is both readable, with a large vocabulary, and stylistic choices. I enjoy hearing the Jagerkin talk, who speak with a certain dialect that is spelled out so you can imagine their accent.
Very early on I noticed something that seemed like deus ex machina, and in my opinion this can be a good plot device when used tastefully, especially if it has been foreshadowed. I know deus ex machina is sometimes seen as a negative thing, but I'm not criticizing anything here. The plot is actually refreshing and original. Highly recommended!
You can find out more on the official site for the book at http://www.girlgeniusbooks.com/.