When you use the right level book for the right level student it is great. There are many other books out there that gloss over all types of grammars, functions, vocab'and pronunciation. However, this does attempt to explore the more important parts of grammar. The grammar is graduated based upon increasing levels of student's ability, which is an important point. Also, I especially like it's drilling of the third person.

It is a good book if you know what you are doing. A text + student does not equal an English lesson. There is more than just the text book in language learning.