What we have to remember about the anthropology books from the 1950s is that most of the information is objective based off of the anthropologist lives. So yes, Mead is very detailed and slightly biased because she has her own personal (western) views. However, this book is a link from gender-essentialism to modern views of how we see the male and female sexes as they exist today.
Long and detailed read- Yes
Great understanding of Male and Female Sexes- Not updated but good overall.
Subjective/Objective ratio- great for her time, sightly different now. (Read with an objective mindset and consider when this was published)
Margaret Mead- Must Know person when dealing with gender and anthropology.