The Weatherby product selector was a sophisticated application of the GoRad Assistant. It allowed the user to specific various criteria, and the possible matches were loaded via AHAH. In addition to advanced product filtering, this system also added product comparisons. The user could compare two products side-by-side.
The selections were ordered in progressive steps. Unlike a basic filter, each step reflects selections from prior steps.
I was only peripherally involved in the project, but it is an exceptional example of the Assistant capabilities. When GoRad is appropriately configured, an application such as this product selector can be configured strictly with CSS+JS+XML -- no PHP! I list this here since GoRad, and the Assistant in particular, were systems of my design and implementation. I am very proud of this!