I don't think the difficulty guitar ratings matter much at the fundamental level. It really does when playing songs, from what I've seen.

I'm doing both Anders' course and Lisa's./sort of back and forth... I think they are both great instructors with different styles...but I think they both will give us a well rounded foundation. Anders might be more for the younger hipper...and Lisa might be for older students at the outset. Personally I think they are both great. Lisa does a good job with tabs and basic chords, even practice advice right in the beginning, and Anders hits the power chords and riff style in rock form a bit more. He tends to like to push more making simpler quicker progress first without as much theory, Lisa likes to mix in reading music/tabs ins a more classical approach right in the beginning.

I think everyone should take both courses, and that way will get a better overall understanding and more practice. Just my 2 cents.