I have heard a lot of people have had intonation and other issues from starting with this method. It is certainly worthwhile but it seems like working on one of the other methods first gives you a more solid basis for it.
Remember, Rabbath did Nanny first.
Also, it solves many advanced issues usefull for solos, etc. but it seems to lack a lot when it comes to traditional bass functions.
I don't advocate being ignorant of this or any other method, but I do think it is best treated as an "advanced" method and not a begining method.