Neither formZ nor ZBrush offers a free trial.
formZ is designed for Freelancers, Medium Business and Small Business.
ZBrush is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for formZ Starts at $439 whereas for ZBrush Starts at $39.95/Month.
Some top alternatives to formZ includes 3D Slash, SelfCAD, SketchUp, Giraffe, Jig Workshop Pro, 3ds Max, Recap Pro, ZBrush and Modo.
Some top alternatives to ZBrush includes Mari, 3D Slash, Strata Sculpt 3D, 3ds Max, Maya, Wings 3D, Modo, formZ and Adobe Substance 3D Painter.