What are some alternatives?
When comparing VR Sketch and Tilt Brush by Google, you can also consider the following products
MasterpieceVR - Powerful VR sculpting & painting tool
SprayPrinter - Convert digital designs into wall art from your smartphone
Snap Art - Snap's augmented reality platform
A-Painter - Paint in VR in your Browser
Blocks by Google - Easily create 3D objects in VR
Poly by Google - Explore the world of 3D