It is NOT a quality rating scale, but an indicator of how much pressure a therapist might bring to your massage. More is not better. It depends on how you want to feel during and after your massage.
Level 1: A light pressure, relaxing massage.
Level 2: A medium pressure massage with no specific trigger point work. Some depth may be achieved as muscled relax.
Level 3: A medium to high pressure massage with trigger point work. This is where we get the "knots" out.
Level 4: A very high pressure massage with trigger point work