I'm not sure if you're asking from a vegan or health perspective, so I will address both: From a vegan standpoint, commercial brown sugar and confectioners sugar are generally not suitable because they are made from white sugar, which is not always vegan (some white sugars are processed with bone char). From a health stand point, they are the same (more or less) as white sugar, however you can make your own from raw sugar, which is what I do. In both cookbooks I mention how I make confectioners sugar, which involves raw sugar, cornstarch and a blender (super easy). Brown sugar is raw sugar with some molasses.