All menu-based search engines have menus, categories and subcategories. Still, there are several differences among them. For example:

* Sites listed - Since submission is done separately to each engine, and every engine makes its own queries, different engines may include different sites.

* Categories - every engine has its own categories, although in most cases, you'll find the  differences between them are minimal.

* Search opportunities - some engines allow for only menu-based searches, while others allow you to combine both menu-based and keywords-based searches.