Salt is salt in terms of sodium content. There are various types of salt and they are different based on the extra minerals that are attached within the chemical bonds. The location of collection or the source of the salt is typically the reason there are different colors. This may impact flavor a little bit too. Different size grains is another way salt is differentiated. Kosher is usually larger while table salt is smaller. Larger grains disolve more slowly. This may impact flavor and can also impact texture of the product you are salting. For example larger grains may be "crunchy" when eaten.