Wheelock is one of the better books to use for learning Latin, both in classroom and private study settings. One of the disadvantages of Wheelock is that more practice assignments are generally needed than come with the standard chapter questions and sentences. Comeau's book is of assistance here.
Comeau follows the same sequence of chapters as does Wheelock, and draws much of his material from the supplementary exercises given by Wheelock in the back of his book. Each chapter's exercises are arranged in four headings - objectives, grammar, drill, and practice sentences. It is in the grammar and drill sections that the real value of this text comes through, given that the practice sentences are already in Wheelock (and the key to them is there).
This is a real workbook -- fill-in-the-blank-type of formatting make it useful for the student to write directly in the book. These could be scored in class, or (where the key is available) by the student himself or herself. There are no supplemental materials here -- no index, no glossary, no key -- as all of these are in Wheelock, and the book assumes ownership of the Wheelock book already.
A useful supplement, this book is worth getting for those who wish to master the material in Wheelock more quickly and more completely.