Randall starts well, but it soon degrades into a sort of thematic history book rather than an explanation of evangelical spirituality. There's good material there, but there's just too much extraneous material mixed in with it. It feels like he gets lost in too much knowledge and doesn't know how to divest himself of the unnecessary names and dates.
It was very helpful to understand the roots of the evangelical tradition and to learn how over time the tradition veered from those (in my opinion) more healthy roots.
Overall a good overview. It definitely focuses more on British evangelicalism, which I know much less about. I wish, however, that it had more from the American side.