Ranked in these QuestionsQuestion Ranking
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.
Pro Textured voxels
Pro Great for game-dev
Exported .dae files are optimized to lowest possible amount of polygons. Despite lack of animation support .dae files can be imported to Blender and animated.
Pro Exports to kv6
Helpful for making larger voxels for Doom.
Con Does not support .obj export format
Con Really buggy
Sometimes it crashes at startup, some large models instantly crash the program, having the mirror function on causes every action to get mirrored (even imports get mirrored).