Ok, I've finished reading The Shack and I'm now prepared to share my thoughts. I'd very much like to hear what other people on this board have to say provided that
they have actually read the book. Please don't comment unless you have or unless you have a question to raise. But, hey, do what you want!

Please keep in mind that these views are my own. If anyone wishes to draw from other peoples' opinions, I'd like to know who said what.
My overall conclusion is that I cannot recommend this book to Orthodox persons for any kind of spiritual insight or revelation. I know that many book clubs have sprung up, literally overnight, because of this book and using it as their spiritual focus. That's good for them, but I would not recommend it for the Orthodox.
Were there any positives? Yes. I thought the book was decently written (a far cry from brilliant) and was a good overall story. I liked the imagery and the sequences. However, I thought most of the characters, especially the main one, Mackenzie, were horribly underdeveloped. I thought the overall theme of the book was definitely worth the time I put into to completing it and that is something that we, as Orthodox, should be cognizant of in our daily lives but all the while being mindful that such reading should always be tempered by our Holy Fathers, Scripture, the Liturgy, the prayer offices, etc.
Ok, my problems. There are a number of them and I shall only go on about a few. First, I really do appreciate how the author did emphasize, throughout the book, that God is a person and that relationship with him can only help us to realize our true personhood. Too many, especially among mainline Protestants, counter that God is merely an idea and that everything in our salvation is a metaphor or symbol. Of course, the other Protestants, mainly evangelicals and such, emphasize God as a person to the point that he becomes your best chum, the person you invite to your BBQ. I think this book was definitely somewhere in the middle ground emphasizing that the Trinity is a unity of love, of lover and beloved, obedience and humility. However, what this discussion of personhood and relationship lacked was any kind of discussion as to how this relationship is achieved. Yes, it is by Grace, but again the lack in Protestant theology of anything sacramental is where the intended relationship ceases to be any actual, physical, spiritual, personal communion with God and is explained and "experienced" more in the realm of ideas which is where the liberal mainline Protestants fall. Again, the lack of any kind of sacramental theology or its lack of practice hinder relationship for Protestants on a more fulfilling level. Another pitfall is that this relationship is explained to be the polar opposite of rules/regulations. Not too long ago, I read a letter in the "Public Pulse" section of the Omaha World-Herald where the author lamented that people are more interested in rules/regulations than seeking a relationship with God and that's why churches are losing membership numbers. In a way, he's right, but we must also remember that for a relationship to exist, there has to exist some sort of framework by which or with which you relate to someone else. If a guy and girl start dating, there is a relationship, but there are a prescribed (whether implicit or explicit) about what each person can do at certain times. You don't just start by sleeping with each other (at least I hope not) and then ask their name! Relationship cannot be divorced from some sort of rule/regulation. Again, I think the Protestant over-reaction to rules/regulations or rituals, stemming from their adoption of Paul's dictum, "The letter killeth but the spirit giveth life" into their new battle cry, is the cause of seeing these as polar opposites. Relationship must be guided by some rules. But at the same time, Christ's saving Passion and Resurrection have lifted us up so that we no longer need fear rules but can start living by the statutes given us by God.
Although I did really appreciate the insistence on God's grace and his mercy as opposed to the Calvinistic heavy handed "You're a sinner and a worm" mentality, there was very little or no mention of repentance. Even Luther acknolwedged in this 95 theses that the Christian's primary duty was to lead a life of repentance, in fact, he lead off with it. "When our Lord and Master Jesus Christ said 'repent', he willed the entire life of believers to be one of repentance." (Thesis 1). There was so much talk rather of purification, of being cleansed by the grace and mercy of God (which I have no problem with) that there was no discussion of what we are called to actively do. We need to actively "turn back." All the times "turning back to God" was mentioned in the book, again, it was dealt with in the realm of ideas. Repentance is not an idea; it is an actual transformation by deeds. Considering how much we hear from people like Osteen and Warren about how Christianity should be "more deeds, less creeds", I was surprised by this. There has to be some actual tangible change worked by our deeds for the indwelling, for the relationship with God to work.
The lack of any sacramental theology or ecclesiolgy was hardly surprising. When Jesus (in the book) describes the church as a mere assembly and not just an "institution" but a "man-made institution" I knew we were dealing with the whole visible/invisible church dichotomy typical of Protestantism. As much as God (in the book) condemned independence of God from man, there was no discussion about any communal aspect to salvation save for extending forgiveness.
These are just a few problems I had with this book. However, I am glad I read it, if only to make me realize that I am so thankful for all that God and the Church have given to me as means to achieve theosis and true communion with our Lord. I would recommend this book as a work of fiction and maybe light philosophy, but as a spiritual platform, no way.
I'd like to hear other opinions.