Christian,

Use a Property_assign emthod when you need to react to a property being assinged a value. The key thing to remember is that simply creating an assign method for a proerpty slows things down as it MUST be fired every time the property is assigned a value. Therefore, if there is another way to do what you need then the other way is probably better in terms of performance.

I have, dio and will use them. However, I don't use them ofter because they are not needed often. When they are needed there is no other way to accomplish the same goal.