This is one of the books that I intend to finish over Christmas break, in between all the grading I have to do. I've gotten through the first three chapters and have found it fairly disappointing. One of the best reviews that I've read on this book is one by my friend and Westminster Seminary prof, Carl Trueman.
What makes Carl's review so intriguing is the larger issues of Christian (and Presbyterian and Reformed) identity that it raises. One of the problems with the "evangelical" construct--when viewed outside of historic denominations--is that there is no shared creed or rituals to define oneself over against a historic body such as Roman Catholicism. As a result, as Carl's points out, comparing "evangelicalism" over against "Catholicism" really is comparing apples and oranges.
What this cries out for is a renewed emphasis upon Presbyterian (and Baptist, Lutheran, Methodist) identity. Only as we well-learn our own historic confessional and liturgical positions will be able to dialogue meaningfully with other communions. Even more, as we learn our historic commitments, we will be able to see points of continuity and contrast in the larger historical development of the Christian tradition in ways that will give a new sense of charity as well as a better position of critique.
If I have more thoughts on the book when I'm done reading it, I may come back and post further...