There is no useful single winner for every traveler. A family that wants restrooms, food, and rentals is solving a different problem from a snorkeler who wants reef access. A traveler carrying a picnic and seeking a low-service park has a different problem again. Start with the services you need, then compare the location with where the day begins and ends.
Magens Bay has the broadest classic-beach appeal. Coki Point concentrates snorkeling, rentals, and food vendors in a compact setting. Sapphire combines water activities with food and beach services. Lindquist is a managed park where visitors should bring food and snorkel gear. Secret Harbour places a sheltered beach beside a resort, restaurant, and dive operator.
Water clarity, swell, wind, seaweed, and wildlife sightings change. Descriptions below explain the usual setup and the services documented by official tourism and operators; they are not promises of a particular day's conditions. Look at the water, follow posted flags and lifeguard direction, and change plans when conditions are unsuitable.