说好不玩VBS来着，但是今天有人问我，简单的写一下吧。
对于这个问题，《VBScript Programmers Reference》第215页说的很清楚：
Functionally, Property Let and Property Set procedures do the same thing. However, the Property Set procedure has two differences:
- It makes it clearer that the property is an object-based property (any technique that makes the intent of the code more explicit is preferable over any other equally correct technique).
- Code outside of your class must use the Set Object.Property = Object syntax in order to write to the property (also a good thing, because this is the typical way of doing things).
从功能上说，这两者的作用是一样的。但是Property Set有两点不同：第一，它说明了这个属性是一个与对象有关的属性；第二，在类的外面给属性赋值的时候必须使用Set关键字。
文件说明太抽象了，举个例子：