I am afraid all these batteries are produced in Asia, Mugen included. If we assume the Japanese one is truly Japanese, perhaps this latter is better, but I doubt it, due to its unrealistic capacity.
Given the obvious environmental concerns related to the manufacture of batteries in China, I certainly prefer to wait until some good alternative is provided by a German company (usually very efficient in these jobs). ATM there's nothing convincing on ebay and amazon.
If you are in Europe this involves in addition having batteries shipped within the EC and no extra customs' costs!