What are the important difference between property clause and visual attributes?

Named visual attributes differ only font, color & pattern attributes, property clauses can contain this and any other properties. You can change the appearance of objects at run time by changing the named visual attributes programmatically , property clause assignments cannot be changed programmatically. When an object is inheriting from both a property clause and named visual attribute, the named visual attribute settings take precedence, and any visual attribute properties in the class are ignored.