It pays to learn from an experienced and professional guitar instructor.  For over twenty years I've been teaching guitar as a full-time profession.  Being a musician is one thing, but having the ability to communicate musical concepts and actually 'teach' guitar is in itself a unique skill or craft that takes years to develop.  I still see improvements in my own approach to teaching every year, so I know that there is no substitute for experience, and learning from a experienced professional can save an aspiring guitarist hours of frustration in learning from books, videos, or other less-experienced instructors.