I read this book in a graduate level theory and methods seminar (scratch that--I read it twice). If you study religion at the undergraduate or graduate level and have never read this book, I highly recommend it. A word of caution: This work is polarizing. If you are fond of uncritical approaches to religion, then you probably will not like this book. On the other hand, if you tend toward sociological/marxist/poststructural theories of religion and/or don't mind methodological reductionism, you'll likely enjoy what you read.
If anything, it is a challenging and thought-provoking read--it will almost certainly make any religious studies scholar think critically about his/her own presuppositions and probably improve his/her scholarship.