I have only reached page 42 (I started reading Wolf Hall, which turned out to be a MUCH more interesting and intelligent book ) but until now (and of course, it’s still too early to say much) I am not very impressed. It’s a good summary of some basics, but the approach is too conventional and not “rich” or especially insightful.
Until now. I may change my mind later.
A few minor random observations:
Chapter one is a good quick description of where Muslims live and what sects there are (of course, population figures are out of date). But it may be unnecessary to even bring up the fact that “more Muslims live outside the middle east...” because crucial theological and ideological questions are all being fought out on a middle-eastern basis. To the extent that Islam is an issue in the political life of Muslim countries, it is an issue with an almost exclusively middle-eastern history and background.
Chapter 2: p-20’s description of the “Muslim view of Christianity and Judaism” (that Judaism and Christianity are partial revelations, later completed by Islam) is one way some Muslims may look upon this issue. But others (probably more numerous in the general public, and certainly more representative of the Salafist, Wahabist and Maudoodist view) will place emphasis on the fact that God sent an (in its own way) complete revelation to them too (maybe different in some details, but not “partial”) but they have corrupted it. What they now know as Judaism or Christianity is NOT what God sent them. This last point is crucial.
P-21: West Pakistan’s violent suppression of Bengali nationalism is a very poor example of the “narcissism of small differences” that Brown is discussing here.
P-22. This is extreme nitpicking, but really, the way Muslims see Western power today and the way Christendom saw Muslim power in the middle ages are NOT symmetrical opposites.
P-26. The principle of “no compulsion in religion” was historically NOT the basis for tolerance it is now advertised to be. Tolerance was very real in many periods, but it was pragmatic. When less pragmatic rulers decided to be intolerant, masses of clerics and divines did not stand up to say “but you are violating the principle of X”. The principle is a recent discovery.

Btw, if you are interested in comparing monotheisms, professor FE Peters is your man. Really amazing scholarship. http://www.goodreads.com/author/show/397928.F_E_Peters