Hi Chris,
I'd like to reply public, as I think, there may be more readers interested.
Sorry to say, I don't think the course is very good to non-german speakers. The main advantage over the countless other courses is the forum. That works in the following way:
You get your lessons via email, from the usual basic child-songs to current pop songs and oldies. You study the lesson and train to play the song you got. When you feel confident about your result, you record it and upload it to the forum. Then the other participants can give you feedback about how you played it. One of the learning goals is to hear and analyze to recording of the others, for being able to analyze you own recordings. After the first very basic lessons you are requested to upload an self-analysis together with your song. After some days - to give the other students a chance to do their feedback, a teacher will give you the 'official' feedback. Depending on that you can iterate on the song or continue with the next.
The problem for you is, that everything is in german.
Hope that helped
Yours
Rainer