Great book overall. I appreciated the exhaustive detail, the description of events from multiple perspectives, and the complexity of the story line. Some real big moments of good or bad luck were required to propel the story, but suspending my disbelief was easy enough.

Others complain about the representation of Islamic terrorists as in some respects racist or otherwise discriminatory. The fact of the matter is, many different ethnic groups are presented to the reader, not just Muslims. I would argue that the representations of Russians and Chinese is just as potentially racist as the description of Muslims. The issue of race and racism in the book is far more nuanced than Stephenson simply picking on Muslims.

One thing I did appreciate was the nuances with which the "Jihadists" were treated. The Jihadists were actually a rather diverse group of people, including North American born and even white people. This might actually contradict the common racial stereotypes of Islamic extremists. Further, Stephenson does make rather plain that these jihadists are extremists, not your "every day" muslim.
This is not to excuse Stephenson of any discrimination, stereotyping or other racializing mis-steps, but rather to suggest that it is hard to argue that he his picking on a single racial/ethnic group. Any discriminatory or racializing mis-steps taken by Stephenson are not isolated to Islam, and are more nuanced than a simple stereotype. Any critique of is treatment of "race", ethnicity, and religion needs to explore the more subtle ways these issues are manifest.

Some others have criticized the very choice of Islamic extremists, as if pandering to the post-9/11 milieu. I would argue that the choice of Islamic extremists seems to make sense given the general state of global politics. If one were to pick an internationally organized group what might be interested in launching an attack on the United States in the last two decades or so, a group of radical muslims seems a reasonable choice. What are the odds of an internationally organized group of radical Jews, Turks, or Spaniard, launching an attack on the US? Pretty slim (of course, there are plenty domestic, non-islamic acts of terror, but I think Stephenson was really interested in exploring a globally organized group).