I think the main problem of his work is that he does not acknowledge the role of class struggle in Europe and America - which is far more fundamental for understanding their historical development than, say, its slavery roots via Roman law or plunder of the New World. The critical piece that you cite mentions this.
As I see it, Graeber has a fish to fry with Marxists and manufacture an intellectual basis for his anarchist anti-statist and anti-institutional views. I think he fails in this respect miserably, as his views smack of neoliberalism sans the cult of money, but other than that - his book is a nice overview of the anthropological literature on the subject which is not well known in the US.
I do like his critique of the neoliberal economic theory, though. Obviously it did not originate with him, but his book provides a lot ammunition against this theoretical framework.
-- Wojtek
"An anarchist is a neoliberal without money."