Does the business work if you work it?

No. Amway-The Dream Or The Scheme explains:

Let me make a disclaimer that some people do make significant money from Amway, but most of those folks are tenured diamonds who are almost in an exclusive club. There is only a short list of new diamonds that I know of in the US, and I have heard that even these new diamonds may have had legs in other countries. It would seem that Amway is not growing in the US and Canada. Also of note, Amway did not release figures that are separate between Amway North America and the rest of their overseas operations. . . Few people will even bother to see the plan once you mention "Amway" and for those who are open minded and motivated to register end up having to deal with a hard to sell opportunity along with high priced common commodities such as soap, vitamins and energy drinks. It's pretty easy to see that the business does not work, even for most of those who actually work it. There are simply too many issues with the business that handicaps those brave enough to try. It seems even the fiercest defenders of Amway are unable to provide a shred of evidence that they have actually made a profit from this opportunity.

Also, the blog has a comparison of the cost of Amway Global products with Costco.