What are some alternatives?
When comparing Tilt Brush by Google and MasterpieceVR, you can also consider the following products
Snap Art - Snap's augmented reality platform
Oculus Medium - Sculpt, model and paint in virtual reality on a 3D canvas.
SprayPrinter - Convert digital designs into wall art from your smartphone
VR Sketch - A tool for designers to draw inside virtual reality
A-Painter - Paint in VR in your Browser
Blocks by Google - Easily create 3D objects in VR