I think it's mostly somewhere in between "the basics" and "everything." I haven't used everything P5 has to offer, certainly not all on one image, but I certainly use the options not available in P4/PP. Usually at least some of them in every render.

For my entry in the "Equine Beach" challenge, I used more than usual, because no postwork is allowed. The horse's mane and some of the human's hair is dynamic hair. The kilt is the skirt from Pdxjims' Fantasy Set for David, clothified. (The figure is actually M3-to-M2, but one of the joys of dynamic cloth is that it's pretty easy to fit clothes to other characters.) The drape/cloak thing flying behind the figure is the high-res square, clothifed. (I constrained the top, and applied a wind force to it until it was a shape I wanted.) Some of the textures make use of P5 nodes. And my signature is a displacement map on a rock. (Yeah, I know it's a little distorted. I'm a sucky texturer, but I try!)