It is a good app to review moves learned in lessons you have already had. I say this because the dancer used in the videos is not all that great at isolating. This would cause a beginner using this to learn incorrectly and think it is fine for the whole body to move that noticeably when trying to do certain isolations. She appeared to be pretty good at arm movements.
rasperella about The Belly App - Your Belly Dance School for Beautiful Fitness