PRS actually has four neck shapes: Wide/Fat, Wide/Thin, "Regular," and the Santana Carve.
W/F and W/T are by far the most common, with "Regular" only being available on certain 24-fret models and the Santana carve being exclusive to the Santana signature models (surprise!).
I've never played the Santana carve, but of the other three I prefer Regular the most and W/T the least, but W/F is a nice chunky carve that is still very comfortable in the hand.