When comparing VoxelShop vs Paint3D, the Slant community recommends VoxelShop for most people. In the question“What are the best voxel editors?” VoxelShop is ranked 3rd while Paint3D is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pro Textured voxels
VoxelShop is Open Source. You can download and use the software for free, but donations are encouraged to support the project.
VoxelShop is available for Windows, OS X and Linux.
Pro Export to COLLADA
Pro Exports optimized meshes
The export (to DAE files) removes unnecessary geometry, creating an optimized model.
Has a free trial version and a cheap full version.
Pro Scripting support
Can be used to generate models, import stuff, animate, etc.
Pro Can export traditional 3D models
Pro Interoperates with 2D paint programs
Pro Supports multiple voxel formats
Pro Easy to use
Pro Uses 32-bit color with real volumetric transparency
Pro Supports both "per voxel" drawing and smooth "sculpting"
Con Does not support .obj export format
Con Not easy to export to .qb when there are many models
Con The web site's domain is no longer available
Using the WayBackMachine to get the site's contact email address, I attempted to contact the developer to find out what the story is. There has been no response. The WayBackMachine's last archive date for the site was 11Jan2016. Their cached version of the paint3D.net's forum does not have any post explaining what happened.