Stephen Prothero writes in his latest book, God is Not One (HarperOne, 2010) (see the latest review):
Christianity is now so elastic that it seems a stretch to use this term to cover the beliefs and behaviors of Pentecostals in Brazil, Mormons in Utah, Roman Catholics in Italy, and the Orthodox in Moscow. (p. 67)
Verily, I think it is a stretch. But my Mormon friends don’t.
Notice the section in the book devoted to Mormonism (pp. 82-84).