What are some alternatives?
When comparing Chief Architect Premier and ZBrush, you can also consider the following products
Maya - Maya in Launchpad
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Cinema 4D - Cinema 4D is a 3D modeling, animation, motion graphics and rendering application.
MODO - Modo by Foundry brings you the next generation of 3D modeling, texturing and rendering tools in a powerful integrated software package.
MakeHuman - MakeHuman is a free, open source, interactive modeling tool for creating custom 3D human characters.
3D-Coat - 3D-Coat is the one application that has all the tools you need to take your 3D idea from a block of digital clay all the way to a production ready, fully textured organic or hard surface model.