This book was mostly good. It contains a certain degree of practical advice which most parents desparately need, and yet avoids the pitfall of similar books (i.e. To Train up a Child) which are based on the Hullian Behaviorism of Skinner, Watson and others.
My only complaint is that at times, the authors appear to take some liberties with scripture which are not known to the text (for example, claiming that scripture defines the rod as a "thin stick ...what we would call a switch") all the while citing scriptures which do not support the statement. Sure, this is probably inconsequential, but it reveals a propensity to read their definitions into the Biblical text rather than remaining silent where scripture is silent. While this is a criticism, it should be taken as an encouragement to search the scriptures given as citations to ensure that they truly support the authorial interpretation. We are all guilty of doing this so I don't want to belabor it or be overly critical. They are much more Biblically literate than the Pearls and they have a solid reformed presupposition which is clearly lacking in the Pearl book.
There was one peculiar moment in the book in which the authors seem to endorse the Romish tradition of the "seven deadly sins" when perhaps a better example which would have illustrated the point even better would have been to cite the "six things the Lord hateth, and seven that are an abomination to Him" from proverbs if they were wanting seven examples, but again, this is perhaps nitpicking on my behalf. I found very little with which to disagree in this book a day heartily recommend it to others who want practical down to earth ideas and a reformed, dominion oriented theology of discipline.