What are some alternatives?
When comparing Kodon and Mari, you can also consider the following products
A-Painter - Paint in VR in your Browser
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Oculus Medium - Sculpt, model and paint in virtual reality on a 3D canvas.
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.
MasterpieceVR - Powerful VR sculpting & painting tool
ZBrush - ZBrush is a digital sculpting and painting software solution.