There is a common thing in all of the anti-God-and-religion books, which is the misunderstanding of some of the major points and ideas in religions, especially Islam.
For example, in this book Hitchens says that in Islam, and according to the Koran, apostasy is punishable by death.
This is actually wrong! Koran never said that apostasy is punishable by death! In fact, apostasy has no consequences in the Koran. On the contrary, according to the Koran, people are free to believe whatever they want! There is no punishment whatsoever.
The major problems with Hitchens and other atheist writers is that they write about Islam without really understanding it or even reading the Koran fully and thoroughly. They confuse many personal beliefs of some Islamic groups with the Koran.
Generally speaking, this book has many good points. But the amount of bullshit is still much greater!