Since my own opinion could hardly be objective (R. Rapoport thanks me for my contribution in A Note To The Reader), here is what Professor Elliot
R. Wolfson of New York University, author of Open Secret, has to say:
In Afterlife of Scholarship, Chaim Rapoport offers a meticulous critique of Samuel Heilman and Menachem Friedman, The Rebbe: The Life and Afterlife of Menachem Mendel Schneerson, published by Princeton University Press, 2010. Rapoport challenges many of the assumptions made by Heilman and Friedman, and argues, through close textual reading, that these assumptions are based on interpretive flaws and/or lack of knowledge of Hasidism in general and of Habad in particular. Despite the overtly polemical tone, Rapoport's criticisms are never offered ad hominem. On the contrary, he painstakingly documents every point of contention, and has thereby provided ample evidence to allow other readers to assess his arguments against the portrait of the Rebbe presented by Heilman and Friedman. Whatever one might decide on the merits of his analyses, Rapoport's volume provides an invaluable treasure-trove of sources for future generations of scholarship on the seventh Rebbe of Habad-Lubavitch.
While on the subject of the Rebbe's biography and persona, two recently published letters (available here pages 18-26) are worthy of attention: