In saying that, I'm not disregarding what his personifications of the persons of the Godhead may mean. I don't think it's an accident that his Godhead, and also the wisdom personification that makes an appearance in one chapter, are given racial appearances that in the US would be considered minorities--African-American, Asian, Jewish, and wisdom is Hispanic. Much like how McLaren puts his words into the mouth of the Jamaican Neo in some of his books. One could point out that the last appearance of the Father was of an older man, though even with it we are not given anything about the race of the appearance--are we to assume the Father in this appearance is Anglo because no other race is given, or is He still African-American like previously because nothing is said about it?
Having said all that, though, I have to admit I was impressed that he takes it seriously, and seems to put forth the Trinity as being true.
We are not three gods, and we are not talking about one god with three attitudes, like a man who is a husband, father, and worker. I am one God, and I am three persons, and each of the three is fully and entirely the one
I think that statement is pretty strongly trinitarian.
There are some interesting occasions in the book, when Mack is talking to one of the persons only to have the conversation continued with another of the persons, which disconcerts him a bit.
Another thing that I could appreciate was what was said about good and evil. It really is quite an insight into the nature of relativism, and in defense of absolutes
Then it is you who determine good and evil. You become the judge...And then beyond and even worse, there are billions of you each determining what is good and what is evil...
And if there is no reality of good that is absolute, then you have lost any basis for judging. It is just language...
Perhaps no plainer judgment and conclusion could be made against the whole postmodern trend.
One more thing to note, positively, are his views on Heaven.
This life is only the anteroom of a greater reality to come. No one reaches their potential in your world. It's only preparation for what Papa had in mind all along.
If you've read some of the more recent emergent writings, or what I've posted here about them, you'll know that they are pushing the view that redemption is something here on earth, the kingdom of heaven is something here that needs to be made reality, and even from McLaren are hints that he thinks along the lines of full preterism, that all prophecy has already been fulfilled.
These are a few things I agreed with in the book, and they're not small things, either. His views on the Godhead, on absolutes, on Heaven, and on other things as the resurrection, put him miles ahead of many of the louder voices out there--the emergents, the Jesus Seminar nuts, the postmoderns. In that regard, I find it reassuring that this book is rather more popular then any of their works have yet to be (I can imagine one emergent author calling it something like "jejune", like he did the Left Behind books).