These monsters use an element from Link Monsters, as they need specific monsters to Summon. However, the main difference is that the Materials are shuffled back to the Deck instead of being sent to the Graveyard. What makes these monsters different from others in that aside from a broad limit usually set on the Materials, there are no restrictions on what can be used, as Levels do not factor in with Composition Monsters.
Maestro Monsters do not have Levels. Instead, they have a Bass. A Maestro Monster's Bass shows music notes instead of stars.