What makes a country more or less attractive from another for expansion through merger and acquisition, and if some countries are better suited for such purposes, why?

International markets provide a tremendous opportunity for business expansion for a variety of reasons by merger and acquisition.

Answers that are short and only in list form,

What are the principal reasons for an existing company to seek out global markets for expansion through merger or acquisition rather than seeking to expand internationally directly through foreign export sales?

What makes a country more or less attractive from another for expansion through merger and acquisition, and if some countries are better suited for such purposes, why?