I'd been playing guitar for a few months before I bought Guitar Coach, so I initially thought I was too advanced for the beginning lessons, but the more advanced lessons were quite challenging and as I progressed, I found myself referring back to the earlier lessons to ensure my technique was correct. By the end of the course - there are five levels each consisting of a series of lessons to develop different aspects of your playing - I found I really did need to have a good technique to have any hope of mastering one of the more difficult pieces (a rollicking version of La Bamba).
The product is really easy to use, advances at a nice rate and has great videos to ensure you are doing things correctly along the way. My main gripe with the videos is that you find yourself continually clicking on the mouse to rewind and play again (I notice this problem has been overcome in the Guitar Coach Intermediate version with a loop option). So in this regard a new release of the product to fix the issue would be most welcome. One of the best features is the variety of songs and styles that are provided across all of the lessons.
A possible downside for the purists is that all of the material is presented in TAB format, and there is little music theory presented. I would argue that adding this material could be at the expense of a beginner's enjoyment, which seems to be a real focus. I must admit that I am at the stage where I'd like to have a few different scales and theory elements to work into a more regimented practice routine, but hey, I can always buy a book or even better, get myself a human coach ($$$). For value, I'd say Guitar Coach is the real deal.