When comparing Sproxel vs VoxelShop, the Slant community recommends VoxelShop for most people. In the question“What are the best voxel editors?” VoxelShop is ranked 3rd while Sproxel is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Pro Multiple export options
Exports to OBJ, MTL and 3MP.
Pro Free, open source and cross-platform
Sproxel is a free voxel editor that's available for Window and OSX. It's licensed under the New BSD License with source code available here.
Pro Intuitive UI
Pro Textured voxels
VoxelShop is donationware. 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.
Hasn't been updated since 2012.