I have used this exclusively for my students from very binger thru intermediate for many years. It is BY FAR the best integrated method with written work, technique and creative pieces all combined into each unit---thus there is not a lot extra to purchase for this method. (I do provide extended theory exercises and supplementary material based upon grade level.)
What impresses me the most are the creativity/originality of many of the lesson pieces. They are just fun. I've never had a student be board with this method....unless they simply don't practice. But enjoyment means practice and practice means enjoyment. You can't get around that!
This is a highly interval-focused course, and if you use it the way it is intended, you will have students with great technique, understanding of music and wonderful sight-readers.