Overall Dr. Horton's book is excellent, particularly chapters 4 and 5. He does a tremendous job of locating the constitution of worship in Scripture and of addressing the narcissism so unfortunately prevalent in the church today.
I did find his virtual assault in chapter 2 on believers experiencing God somewhat overdone. Granted, there is far too much seeking of the experience in the church today, but that does not and should not be taken to mean that a believer cannot have some kind of experiential reality of God. Further his observations in this area seem to neglect passages like Psalm 27.7-9. And his discounting of believers seeing God at work in the present "The world is shot through with divinity and nearly everything and every experience is an opportunity to touch and see God's face" (pg. 39) seems to emphasise God's transcendence at the expense of His immanence, the latter of which is also confirmed by Scripture, e.g., Psalm 19, 50.6, Romans 1.20, etc. The overall thrust of this chapter suggests that it is impossible for a believer with, for lack of a better phrase, their theology straight, who is seeking God in accordance with His word, to witness God in His creation, which again seems to me to contradict Scripture. It is true that these experiences are not means of saving grace as defined in Scripture, nor should they be mistaken for or sought as ends themselves, but that does not - when they are truly of God - diminish their reality or significance in the life of the believer.
Insofar as the reference to ministers being formally sent or approved by an ecclesiastical body, "And, by the way, Paul clearly understood 'sent' to mean sent by the church through its appointed officers, as his insistence on the laying on of hands reminds us" (pg. 42), while that is true, I would offer that what Paul did not have in mind are the formal scholastic hoops now required by many of those same bodies before they will even consider recognising (much less ordaining) a person as a minister. The idea that one cannot be a theological sound and truly called minister unless formally educated and ordained (which seems to be what Dr. Horton is getting at) is contrary to the Scripture to which he appeals. Timothy had no formal education that we know of other than being brought up with an understanding of the Scriptures and his being mentored by Paul. Neither did Titus, or for that matter Peter, James, John; nor in all likelihood did the many house church leaders like Priscilla and Aquila, Nymphas, etc. While I agree that seminary and ordination is the common and perhaps even preferred route into ministry, that does not mean that God cannot/does not sometimes call and equip people without their having done everything according to some set of denominational rules and requirements.
In closing, while the bulk of this review takes issue with the author's views as mentioned above (thus the 4 star rating), the book on the whole is well worth reading. It speaks particularly to a serious problem in the church today and should be read and heeded by far more people than it probably will be.