Short review: this is really a memoir of Christian maturity. Zahnd is recounting how his faith was enlarged because of how he encountered the sacraments and Christian history. I think we need more stories like this and I have been encouraged by Zahnd's other books prior to this.
What I think is probably most helpful is moving Christianity from an event to a process. The quote that really sums it up, “As long as our churches are led by those who view being a Christian primarily as a kind of conferred status instead of a lifelong journey, and view faith as a form of static certitude instead of an ongoing orientation of the soul toward God, I see little hope that we can build the kind of churches that can produce mature believers in any significant numbers.”
My full review is on my blog at http://bookwi.se/water-wine-story-brian-zahnd/