...someone with over 14 years experience. I've taught for both Kaplan & The Princeton Review. I've also trained teachers and written material for Kaplan.

...whoever happens to be available to teach your class. Perhaps a qualified, talented instructor, perhaps a beginner or burnt-out veteran.

...based on the needs of the class or the student being tutored You'll spend time only where it's needed, given your strengths and weaknesses.

...based on a book. You'll slog through lessons you don't need and zip past areas of concern to you.

...questions from actual exams and customized material.

...poorly-written material that can do more harm than good.