I agree that we should feel empowered to constructively critique the work of other trans folks without being accused of saying an entire book (or worse, person) is worthless. FWIW, I saw Julia Serano speak recently at the launch of the second edition of Whipping Girl, and she acknowledged that quite a bit has changed, both in society and her own mindset, since she first wrote it.
I haven’t yet finished reading her second book, Excluded, and I don’t remember offhand if she spoke more or differently about transmasculine or non-binary people in that one; I know she also has a third book coming out soonish. Regardless, as a non-binary transmasculine person, I found Whipping Girl a really helpful read, particularly on the subject of subconscious sex, even though I can’t relate to being a trans woman or transfeminine myself.