Oil-based leather dyes penetrate the leather deeply, so the color goes beyond the surface. The colors are usually vibrant. Since these dyes are oil-based, less moisture is pulled from the leather when drying than with alcohol-based dyes.
Alcohol-based dyed leather when then usually benefit from application of a conditioner to restore some of that pliability before a finish is added. Often, dyed leathers are coated with a finishing coat, to seal in the dye, prevent it from rubbing off, and protect the leather overall.