When comparing SLAB6 vs Goxel, the Slant community recommends Goxel for most people. In the question“What are the best voxel editors?” Goxel is ranked 3rd while SLAB6 is ranked 19th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro idTech1 and Build engine voxel editor
While the idTech engine 1 (aka the "DooM Engine") does not support voxels, newer limit-breaking source ports have added the ability to render the .kvx voxel format designed for the Build Engine. Slab6 is currently the only well-known .kvx editor as it continues to pop up in DooM modding forums and tutorials. Even though it's not the most user-friendly editor, its support for .vox export enables the model to be edited in MagicaVoxel or voxels made in MagicaVoxel (which supports Slab6 (Slab) .vox export) to be converted to .kvx for use in-game.
Pro Open source
Pro GNU/Linux
At least somewhat available for GNU/Linux.
Pro Supports .obj
Pro Available on Android
Pro Simple Interface
Pro Supports procedural rendering
You can script a build for it to render.
Pro Exports to PLY format
Pro Available in Debian/Ubuntu repository
If you don't have it installed yet, just enter "sudo apt install goxel && goxel" on the terminal, and you will be running it in a few seconds.
Pro Available on iOS
Works nicely with Apple Pencil.
Cons
Con Not very user friendly
If I asked most people to use this to draw something without reading anything about the program, a good percent would not be able to. with odd controls like 'Insert' to draw, 'L' to open, and no customization on these controls, its requires users to read how to use it. the help guide only gives you a basic understanding of how things work and requires you to search through files in order to fully understand how powerful this tool really is. If i were to rate this for how user friendly it is on a 1 -10 scale (with 1 being like binary switch panels, 3 being ms-dos, 5 being a minimal gui with a complex console command line for all functions, 8 being able to sit down and perform basic operations, and ten being no effort at all,) I would give this a 7(has a gui that is easier to navigate but even simple functions require a bit of reading).
Con Hasn't Been Updated in over a year.
Con Missing docu/tutorials
Finding help on e.g. using materials is missing or not easy to find.