If you liek walking along the beach this is for you. You pass all the turbulance of the first beach and pass the quieter second beach. On the third beach then there are hardly any people. It's beautiful and quiet.
Beach is great to embark on the boats that take you around the island. Not the greatest for beach bums since at high tide the sand is gone up to the board walk. Some great pousadas (Corais) in this stretch but prefer quarta praia for sincere tranquility and joy of beach life.
Beach 3 is a short stretch of sand in an "unswimmable" rocky area in what I would call the in-between beach between the mayhem of Beach 2 and the tranquility of Beach 4. Nice to walk along, but I would recommend Beach 2 or Beach 4 (or Gamboa) depending on what type of atmosphere you like.