SPS coral, is a favorite among experienced coral hobbyists. They can be found in a variety of unique colors, shapes and sizes, usually found as either plate like, or branching corals. All SPS corals have a hard or stony skeleton created by aragonite, and often formed into cup-shaped structures called corallites and is covered by a thin layer of tissue called the coenosarc. The foot of the polyps then grows from the coenosarc on these colonial corals, or attached directly to the substrate connected by a pedal disc. The rate that this occurs depends on the species. Some varieties of SPS corals can grow very quickly while some other varieties take seemingly forever to show any growth.
As well, due to its skeleton, SPS coral frags require a consistent source of calcium, alkalinity, and magnesium to thrive. They also require a good amount of light and high-water flow compared to LPS. Also, SPS are generally considered more difficult to keep than the LPS or soft corals and are not recommended for beginners.
As with any rule, there are a multitude of exceptions. For example, there is a world of difference between an Acropora and a Seriatopora when it comes to coral husbandry despite both being SPS. Green slimer, red monti or any of the Digis are a good place to start and also encourage hobbyists to research each of the SPS corals to determine their individual care requirements.