I've had the material for a few months now I found it to be the best with the full review (but I've been working slowly) and I'm into the fifth session out of twenty. So far I'm learning how to read standard music notation, which is good since I never learned how.
The material is very professional and well produced. Each lesson is broken up into different sections, the lesson itself with the instructor, the homework assignment, and a workshop where you can do the exercises with the instructor to make sure you are up to speed before you move on to the next lesson. There is a workbook that has all the lesson material in it as well. It's a lot of music theory, which is good since I never studied it before. There is a forum available where students who purchased the material can log on for free and dialogue with other students and also have questions answered by Steve Krenz, the creator of the material. He also makes available on the website additional material for students at no extra charge.
I think if you've never had professional lessons before, and you want to get the most out of your ability and instrument, Learn and Master Guitar is a very well thought out and sufficient instructional series that a beginner to an advanced guitarist can benefit from. I believe Steve Krenz has an advanced degree in music and extensive experience as a professional musician. I wouldn't hesitate to recommend the material to anyone. Maybe in six months to a year I will be able to give a more technically detailed review since I'm sure I will know more about the foundation of music and how it is made on the guitar. It's nice even now to get beyond the basics of just strumming. Hope this helps."