The customer reviews you may have read at Amazon are fairly accurate, as Oldenbourg's background as a novelist creeps into her narrative style. As long as you remember to properly account for her biases, though, it shouldn't prove a problem. At the very least, the bias she brings to the topic is fairly easy to notice, which makes it easy to adjust for.
Your syllabus makes it clear that large scale survey titles are not really appropriate for this project, and so I wonder if a book on "The Crusades" might not be too broad. If that's the case, you might try
this title , also by Oldenbourg, as something a little more focused on a single event. I don't think that the book you found is necessarily a bad choice, and given the availability of some of the other recent books on the subject, you might well snap it up.
A couple of other titles to mention are
The Crusades: A Short History, which appears to still be rather widely read, and
The Crusades: a History , which is the most recent book-length overview of the Crusades, but suffers from post-September-11th Syndrome.