When comparing MagicaVoxel vs VoxelShop, the Slant community recommends MagicaVoxel for most people. In the question“What are the best voxel editors?” MagicaVoxel is ranked 1st while VoxelShop is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free

Pro Actively developed
MagicaVoxel is constantly being developed with new releases bringing bug fixes and new features being released on a constant basis.
Pro Has isometric view mode
Has an isometric view mode for people who are doing isometric drawings.
Pro Realtime render
The viewport renders the objects in real time. Changes made to lighting and materials (such as reflectivity, opacity, etc) are instantly shown on the screen with minimal to no delay. The renderer also allows adjusting things like FOV.
Pro Very easy to use
MagicaVoxel has sane defaults and an intuitive interface. You add or remove voxels with the left-click and rotate the camera with the right-click. The interface does not overwhelm or get in the way, yet it keeps all functionality within easy reach.
Very helpful for beginners is the fact that hovering with the mouse over a tool shows hints on how to use the tool. The hints can be found at the bottom of the interface.
Pro Keyboard shortcut cheat sheet is available
A list of all keyboard shortcuts organized by category is available on the website.
Pro Great workflow
Bake possibility, easy to create a custom palette. Not even in version 1.0 and it's already great.
Pro Imports and Exports as .obj
Pro Excellent rendering mode
Pro Free
VoxelShop is Open Source. You can download and use the software for free, but donations are encouraged to support the project.

Pro Cross-platform
VoxelShop is available for Windows, OS X and Linux.
Pro Export to COLLADA
Pro Textured voxels
Pro Exports optimized meshes
The export (to DAE files) removes unnecessary geometry, creating an optimized model.
Pro Layers
Pro Exports to kv6
Helpful for making larger voxels for Doom.
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.
Cons
Con Small sizes
The maximum dimensions for one voxel is 126 x 126 x 126. To put this into perspective, the kvx format (an older format by ken silverman used in games like blood, shadow warrior, and ZDooM-based ports) has maximum dimensions of 256x256x255. while newer versions of magicavoxel include a world editor (in which multiple voxels can be arranged into a set), each voxel is exported separately.
Con No Linux
Works only on Mac OS and Windows.
Con Unsuitable for game-dev
Only usable format is poorly supported .obj; besides that, the exported models have vertices for each color on, making the vertex count very high and FPS of final game very low.
Con Bad model mesh exporting
For video game development, it's needed to rearrange some of the vertices, builds triangles per color, instead of one big mesh. It's tedious to solve but gives overall nice results.
Con Does not support intelligent palette merging when importing a model as a brush
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).