Yes, it's very effective...for me, anyway. I actually spend most of my time with it singing along with the scales and intervals while I'm driving (alone, that is, LOL).
I think it is a great way to improve your pitch and time.There are ways to use the set to improvise as well. The possibilities to harmonize with the exercises add even more ways to use it. Highly reccomended.
I have used this, and I won't say no useful, but I did find my intonation got better praticing scales slowly with a tuner rather than this method. I think going without forces one to develope ear and hand coordination faster IMO...
