As a theologian and historian I found the book quite interesting, but as an artist I found it somewhat lacking. While he does a fairly good job of explaining why Roman Catholic art is "religious" but not "iconographic" (the former because of it's subject matter, the latter because it is essentially too naturalistic) he does not explain where the formal line of demarcation is between religious art and iconography. One wonders what he would think of the art of westerners like Duccio or Massacio, and if their works would qualify as icons in his mind. Artistically his theories are extremely vague, and leave enough wiggle room to allow for quite a variety in iconography. Perhaps this is a good thing, and perhaps it explains the great deal of variety in iconography that has always been out there. While his theological ideas are, however, very enlightening and much more objective (e.g. the icon portrays a transfigured man and universe) how he translates that into actual composition and technique is an entirely different matter. To some degree his dismissal of Renaissance and Baroque art is very subjective - as in his critique of a painting of St. Agnes where she is scantily clad, thus leading him to ask, "Who could pray before an image like that?" The answer is "lots of people." I have been told by many people in my day that they do not see icons as being images that lead one to prayer and devotion! So, the subjectivity of art is unavoidable, even in "religious" art (iconographic or otherwise).
The book did make me think about whether or not it is appropriate for western churches to be decorated with icons when they are not venerated or otherwise acknowledged in the life and liturgy of the church. Because they play such a central role in the Orthodox tradition, do we not somehow desecrate them if we have them hanging around a church like a decorations? Perhaps not, as he may cite canons from Nicea II that exhort the faithful to display icons all over - even on the street... but still, I wonder.
Overall this is a great book to read, and I recommend it for all artists, especially Christian artists, even if they do not agree with his principles or conclusion. It is certainly the best guide to understanding Christian iconography.