This is what I know about the various versions:
* The Winning Eleven Soccer 10 released in Japan - features the Primera, Premier, Eredivisie, Serie A and various other clubs. I have no idea about the Gameplay, i have heard from various sources that the gameplay is slightly slower.
* Winning Eleven Soccer International - Includes all the above. Not sure if the Nippon Challenge mode is included in this version. If not, then that will be another change from the above
* Pro Evolution Soccer - Same as WE International.
Every year, the new version of the game is released first as Winning Eleven in Japan, and after a few months a modified version is released worldwide, in two different packages: Winning Eleven International for the rest of the world, and Pro Evolution Soccer for Europe.
Additionally, in some countries a localised version is released, featuring local leagues and teams, which could explain Portugal's Divisiao.