This is a really excellent book that I intend to buy for myself, even though it is $335 on Amazon. It contains the Coptic text as contained in the Askew codex, edited by Carl Schmidt. The 385 pages of Coptic text do not seem to correspond exactly to the 174 leaves (348 pages) of the Askew codex. Nor do they correspond to the page numbers in G. R. S. Mead's translation, which end with 324 (though Mead does not note every page change).
I reserved this book because it had notes, which I had hoped meant commentary. In fact, the footnotes generally served to give notice to the differences between this translator's and Carl Schmidt's translation; to reference the writings of various church fathers; and very occasionally to point out intertextuality with other Gnostic works such as the books of Jeu. This means I will have to look elsewhere for commentary on Pistis Sophia.
What really makes this translation outstanding and, for me, worth the price of admission, is that words in the Coptic which are borrowed from Greek are italicized and indexed in the back of the book. This means it was possible for me to pick out the Coptic words in the text and in so doing I was even able to pick up a few words of Coptic. It also enabled the reader to distinguish between synonyms that occur between Coptic and Greek. Mead confusingly translates both the Coptic word for knowledge and the Greek word for knowledge as "gnosis" so we get constructions such as "For it is the gnosis of the gnosis of the Ineffable" which McDermot renders "For the gnosis of the knowledge of the ineffable" which works much better.
I also prefer McDermot's translation because she leaves untranslated certain Greek words which really should not be translated, particularly words like archon and pleroma (Mead translates these) but also words like moira, authades, and heimarmene (I had to look up those last two).
A final very interesting feature of Pistis Sophia is the frequent references to orthodox scriptures. There are a number of Psalms that are quoted in full and then given Gnostic interpretations. Besides this, numerous scriptural allusions occur in the main body of the text. "He who has ears, let him hear" shows up with some regularity. These scriptural allusions are marked with an asterisk and the scriptural reference given.