I recently just finished my BR2 Japan grind, and unlocked enough stuff to get to BR3 Japan. Wow, this is a lot of fun!
It has an amazing SMG, the type 2a, amazing LMG the KE7 which was amazing when I was playing Germany. The BR3 rifle is really good, so reliable
Also, the Ki 100 is an unreal fighter. For someone who really hated being a pilot, it handles like a dream
Only thing missing from Japan is a BR3 rocket launcher / AT device
Overall, from someone who played only Germany and recently moved to Japan, I am absolutely loving it!!