South American giants, and the genus where sexual dimorphism does something spectacular: mature males develop a purple or pink starburst pattern across the carapace that females never show.
That fact drives an unusual market. Males are normally worth less than females across the hobby, because they die within a year or two of maturing. In Pamphobeteus the mature male is the one people want to photograph, which compresses the usual price gap.
They get large, grow reasonably fast, and take food aggressively. Most of the genus trades under locality names and sp. designations rather than described species, because the taxonomy is far behind the trade. Paying a premium for a specific locality is a bet on that locality eventually being described as distinct, which sometimes pays and often does not.