As a concise, introductory text, World Religions examines the ideological and cultural aspects of several religions, offering you a complex portrait of each religion, with scholarly viewpoints interspersed throughout.
I'm a bit of a religion nerd, so I might be biased. But I thought Nigosian did a good job of keeping a fresh, interesting, and precise look at the world's religions.
However, adherents to specific religions should realize that this text is completely secular, and might be lacking the spiritual detail that you're accustomed to.
I'm always very critical of text books, especially college text books. I find they tend to portray a very leftist view of the world, which is completely unfair, especially when colleges brand themselves as being a place of free thinking and open mindedness. So, naturally, when diving into a world religion text book, I was very curious to see how horribly inaccurate certain religions were portrayed. And, thankfully, I was proven wrong. Horribly wrong. It's not that this text book portrayed a conservative's view of these religions, but rather, they stuck to the facts; this is their history, this is what they believe, ect. And, having done research on the bulk of the religions discussed in this book on my own, I'm glad to say they were all portrayed fairly accurately. Kinda wish more text books stuck to cold, hard, unbiased facts, as opposed to the author's prejudices...