Ideal Supplier Site Configuration?

Summary:

Asking for insight or an ideal supplier site configuration per supplier, including suppliers that provide goods or services in multiple countries.

Content (required):

In our previous system we had a supplier site per legal entity (i.e., Australia was "AUSREMIT", Canada was "CANREMIT") and when we implemented Oracle we migrated all of those supplier sites over which has caused us a big headache. Now we are trying to figure out the best way to clean up and configure our supplier sites to make the most of the functionality. Under what circumstances are other companies creating more than one supplier site? What is the logic or what is driving the decision? Thank you!