Unfortunately, this book is somewhat confused in terms of subject matter. It is presented as an account of the philosophy of science of Feyerabend and Lakatos, and (in the early sections) that is exactly what it delivers, with good scholarly analysis and interesting papers by both.
But when it gets into the correspondence, it really becomes quite a different book, simultaneously about politics and personal lives, academic and financial struggles. The correspondence is enormously interesting, but serves to cast very little light on the philosophy of science proper.
All in all, For and Against Method is two excellent short books. I strongly recommend the first half to those interested in the historical era's philosophy of science and the latter to those interested in the history of modern philosophy.
Compositionally, the book is necessarily herky-jerky. But the two independent sections, if treated as such, are very good, and very thoughtfully annotated. It is definitely a rewarding read.