The Polyanthus is in the Primula family, closely related to the Primrose. But whereas the Primrose has one flower per delicate stem, the flowers of Polyanthus are borne in clusters at the end of a much thicker stem. (You would guess this if you knew that "Poly" means "many" in Greek).
Whilst I have to say that I prefer the understated elegance of the cream-coloured species Primrose, there is no doubting that the brash exuberance of the Polyanthus will brighten up any dull spot in the garden. Here in England they are often used - very effectively - en masse, by local Councils to bring colour to municipal parks, traffic islands, roundabouts etc.
In theory, the Primula family prefers dappled shade / partial sunlight, but they seem to me to be pretty tolerant of most soil and sun conditions.
My six plants were in a mixture of colours. One of them has yet to flower, but the other five are all different. Here are some photos of them:
I think I like best the dark red one. Which is your favourite?