here's my take.
its a great book, but if you have a pantheon it probably won't be that useful. if you're buying it for crunch, then don't. the feats and the new class are good, but are hardly any of the book, and it's pretty expensive. i'm not sure it was worth the money for me to buy personally...
so all up, its very good, but has a specific niche. it can be a good influence when doing write ups for your gods, but its certainly not the deffinative book on gods and deities that some claim it is: its the definitive book on GR's gods and clerics, and inspirational because of that.