By common standards, the book might be seen as controversial, but in short, it is definitely an interesting read for those with open-minds.
Written based on personal experience and 'interactions' with God, this book presents the writer's very personal view of the Divine love, implying the life-changing power of a strong faith.
I think the book is enriching, at the very basis, acknowledging that God is absolutely above all religions.
By default a religion defines how we pray. This book, in my opinion, presents 'religion' in a very different perspective - a recognition that God is truly for all, beyond the different religious rituals.
Not many people have the luxury - not to say patience nor willingness - to browse verses/stories from the different holy books of the earth's major religions. This book brings the verses in a non-judgmental comparison, without any inclination towards any particular religious rules, but rather, acknowledged the reference of the holy books towards the single creator of the universe.
For strong believers of any particular religion, this book will not change the way to see God, but I think it highlights enlightening points of view of the different religious beliefs themselves.