Can't really describe the flavor. The flesh is one component, and the skin is another component. The flesh is generally sweet and flavorful, and may have a spice flavor. The peel often has a more acidic component. Some seedlings have a strong essence/taste of the smell of the plant's leaves, and others don't. Seedlings are quite variable, but more are acceptable and some are vary good. In my experience the darker ones are more full flavored, and the orange and red ones are more bland, but but always.
Have had a couple "named" varieties over the years, but they were more bland to insipid, to my taste, though they had larger fruit.
The are harvested by "touch-picking": you gently push up on them with your palm, and if ripe, they will fall off into your have. If you have to tug on them, they are not ripe.
Latin name is Eugenia uniflora, which makes them related to the Eugenias often used for hedges, and which became less popular after the arrival of a psyllid a few years ago that made the leaves distorted.
These are about the size of a nickel or a dime. The shape is ribbed, similar to the "bubble lamps" of the 60s.