African buthids, and the largest scorpions in that family. P. transvaalicus is the common one and it is not a beginner animal in any sense.
Two things set the genus apart. Several species stridulate audibly when threatened, and several can spray venom from the telson toward a perceived threat, which makes eye protection a real consideration during maintenance rather than a theoretical one. The venom itself is medically significant.
Southern African supply is a mix of wild-caught and European captive-bred, and prices sit in the moderate band with real seasonal swing. This is a genus where reading the listing carefully matters, because a wild-caught adult and a captive-bred juvenile of the same species are very different purchases at similar prices.