She has a short, clean writing style. She never lets the writing get in the way of the story- telling. She tells a story that involves the reader quickly and has a plot that moves well. She has sprinkled in a good deal of historical detail, though not all of which I would rely on. That is just not true.
Fowler does have one stylistic quirk.
She mixes story chapters with chapters of historical background, usually with a didactic bent. It is never clear.