Sparko Wood Putty used for filling cracks and holes as part of surface preparation. It does not sink-back or crack and absorbs color to avoid retouching at the end of the finishing process.
Solvent based fillers have a chemical base, and require that you use acetone to clean them up. Solvent based fillers take a longer time to dry than water based fillers.
These are nearly identical to solvent based fillers in utility. They serve to fill holes and repair wood as well as solvent based fillers, and they match up to wood grain to let you stain your wood items again. The primary difference between the two types of fillers is in the clean-up. Water based fillers, by virtue of how they are made, can be cleaned using only water.