When bringing in stuff from Sculptris I would see the same thing. The way I took care of it is by changing the Shader to a different material. Some material shaders show more faceting than others, some show less. I would click around and find one that looks goods and doesn't have much faceting. For sculpting work I prefer the material Pic Mat Clay, it is a beige color. Pic Mat Clay Depth shows faceting, the normal Pic Mat Clay does not.
The second solution would be in the menu at the top under VIEW. Make sure it is set to Smooth Shade, otherwise different modes might reveal more faceting. By default the different modes under view are controlled/turned on by the number keys. Once in a while I would hit one and look at the screen and wonder what the heck happened. I eventually deleted the hot keys for them so I would never hit them by mistake.
Rkhane's post in Importing a smooth object -> shows faces was marked as the answer