There are a lot of people who only use ZB. Mostly I try to avoid to post a rendered picture made in another program. I still work with ZB2 (Mac) and it is the best to use for detailing and a fast render. Mostly I need C4D to make the base mesh because it's more easy, if you work on a Windows machine, maybe Silo or Modo are a good start to use in combination with ZBrush. The renderings made in ZB can give almost the same result like a render in another program but you have to make more, and bring them together in Photoshop. There you can play with it to get the best out of it.
ZB is good 3D program to use for illustrators, it's like a kind of Photoshop 3D. But if you like to render industrial designs, you better can take another program.