You'll have a slightly steeper learning curve when moving from the original GF 1 & 2 to, for example, rock 1 than if you work through the newer versions instead.
There's also a wider range of topics in the newer lessons.
Personally, I think Lisa has such a calming voice that she's probably the best choice for anyone who finds learning guitar to be daunting :)
I wish I had four arms.... Then I could play rhythm and lead at the same time.