For learning, the difference is the time required for induction. It is longer under deep hypnosis. But the purpose is not medical. There is no point in seeking lighter levels of hypnosis. If you find it easy to relax and to isolate yourself from your surroundings, light hypnosis should suit you. Otherwise, try deep hypnosis.
Which type of hypnosis is best for me?
This depends on how much time you have, how easily you concentrate and/or relax.
If you have time on your hands, then deep hypnosis will give you a more intense and pleasant state of relaxation. If you have trouble concentrating or relaxing, deep hypnosis is highly recommended.
On the other hand, if you have little time on your hands, and you concentrate and relax easily, light hypnosis is preferable.
As for child hypnosis, it is recommended for children aged between 7 and 13.
If you find it easy to relax and to isolate yourself from your surroundings, light hypnosis should suit you. Otherwise, try deep hypnosis.