Do a Google search on Filter Test.

Here's a link to one interesting site that takes filters apart. Note that there are more than one grade of Fram filters. Fram filters appear to be cheaply made (you don't get what you don't pay for).

http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html#fram

There is also a description of the differences between the Bosch filter made by Champion and the German made Mann which looked to me to be the same from the outside.

Also note that the filter made by Champion for Mobil 1 is of very high quality and might be a good filter for extended drain situations.