A work like this is difficult to deal with, in terms of whether to recommend it or not.
On the one hand, in many ways it is far ahead of much of what passes for 'Christian' thought today. The author's bold statements about the Trinity, about Heaven after death, about the resurrection of Christ, are statements made in the face of attacks on those same doctrines from various fronts. In that sense, the book is well worth reading.
On the other hand, when he says things that smack of universalism, or tries to make us think that God is our servant, well, those are some pretty serious things, too.
And it's not so easy to simply say to take the good and bypass the bad. Not all errors are equal. How one views the Creation account, for example, may be counted a small matter (though I sometimes wonder about that), but how one views the resurrection of Christ is quite another matter. So when people like Crossan and Borg try to tell us that there was no real resurrection, I have no qualms about saying they have no part in the faith. In that sense, Young is well inside it, and I am glad.
When he tries to tell us that God is our servant, however, I can only raise the eyebrows. I fear how such a mindset would be in some people. Isn't that very much how Word of Faith views God, even up to the point of commanding the Spirit to do thing, and using Scripture almost against God in order to make Him do things?
I think this points to where one of my mains qualms is in the book. His portrayal of God is not one that would cause a Moses to take off his shoes before Him, or make a Job be quiet with unanswerable questions, or strike down a man for having the audacity to touch the Ark of the Covenant, or send plagues upon plagues upon a people for the stubbornness of their ruler, or rain fire and brimstone on some wicked and immoral cities, or give His prophets words about coming disasters and conquests if the people didn't repent.
In other words, the God in Young's book is a rather tame, rather nice, rather domestic diety. Papa in the Shack is usually in the kitchen, cooking, talking about being especially fond of people. It's not exactly the type of being who feels any kind of holy awe or even fear before.
If put to the question, I guess I would say that "The Shack" is by a narrow margin a recommend. It's a book to read with one eye's open, so to speak. If one does so, there is much to consider in it, and some good may be gained from it. If one simply accepts what it says because it sounds good or makes one feel good, then the book has become a stumbling block, and would have been best avoided.