Randall Balmer’s review (BTW, he’s an Episcopal priest):
Central to the priestly claims to authority, Wills says, was the importance of the sacraments, especially celebration of the eucharist, which could be performed, the church declared, only by priests. “The most striking thing about priests, in the later history of Christianity,” the author writes, “is their supposed ability to change bread and wine into the body and blood of Jesus Christ.”
This exclusivity, according to Wills, derives from Thomas Aquinas rather than Jesus. The Thomistic view of the eucharist understands the Mass as re-enacting the sacrifice of Christ, from which all other graces devolve to the believer. The church, following Aquinas, vested the power of transubstantiation — the bread and wine of holy communion actually becomes the body and blood of Christ — in the priesthood. With that magical power, the priesthood increasingly set itself apart from the laity.
Kevin Madigan’s review in The New Republic (he’s not a priest, he’s a historian of Christianity):
Although the Catholic Church has for centuries maintained the opposite position, it is simply false—from an historical perspective—to assert that Jesus instituted the priesthood. Not only was Jesus not a member of the priestly class; it is simply anachronistic to say that any of Jesus’ apostles were imagined in priestly terms, either by Jesus or the apostles themselves.
I remember many years ago when I was lecturing on organization in early Christianity at the School of Theology at Sewanee, and said something like “presbyteroi–whatever that means” and 23 first-year students shouted back at me “priest”–to which I replied, “tell that to Calvin.”
I doubt I’ll read Wills’ book, but my guess is, he’s probably right on. The understanding of priesthood in the western church is directly related to the elevation of the understanding of the sacraments, particularly the Eucharist. As Ballmer points out, Luther offered a powerful critique of that view from early in his career, one that continues to challenge our understanding of priesthood and the sacraments. It’s part of the reason why he was so opposed to an understanding of the mass that involved sacrifice. For Anglicans, that we’ve retained the language of the sacrifice helps to explain why we continue to lift up the office of the priest, but we might well ask whether there are downsides to it.
Preaching Grace on the Square 
The two reviews of Gary Wills’ book that you thoughtfully posted both suggest that Wills has offered his fellow Roman Catholics an understanding of the Eucharist that is more in tune with other contemporary Christian thinkers like John Dominic Crossan. His critique of the medieval Church’s view of priesthood and substitutionary atonement don’t seem very shocking. From an”Anglican” perspective, one could argue that the justification for maintaining the priesthood and the episcopacy stem much more from practical necessity than from medieval theology. In other words, if we did not have them, we would need to invent them (or something quite like them). We are all called to be servants, but not to do the same things or we get in each others way and cause chaos. There were extremely interesting reviews — thanks again for making them available.