I don't suggest Japan. Japanese business school' level is far below U.S. Japanese companies don't value MBA that much, while the foreign companies in Japan prefer to hire U.S. MBA. And the salary in foreign companies in Japan is much better pure Japanese company. In terms of student quality, I am sure you will be disappointed, as most Nui Japanese go to U.S or Europe study.
And, You can still practice Japanese with Japanese students while in U.S. At the mean time, your English will be much better. In that way, you will have more opportunities after graduation.
I've heard a lot about Penn State. It's a pretty good school. I suggest that you come to the U.S. to finish your MBA. If you have good English and Japanese skills plus a Penn State MBA degree, you'll have no problem getting into big firms after graduation.