Okay, my turn.
So far I think I have only battled one, maybe two(can't remember) Japanese players, and I lost. However, I lost because I didn't really care. I got "tricked" with Flash Fire/Volt Absorb switching. For example, the battle started out with My Charizard VS their Scizor. Now, no one in their right mind would have kept a Scizor out vs a Charizard so as I figured, they switched to a Flash Fire Arcanine. However I didn't care and used Flamethrower anyway. Then Charizard fainted I sent out Jolteon. Arcanine had one hit left in it, but I decided to think ahead. Instead of useing a powerful thunderbolt to take off 2Hp, I used Hidden Power:fighting instead, and sure enough the opponent switched to a Traceing Proygon2 which walked into a super effective hit.
So in my oppinion, It's not that Japanese are better, but they just take everything more seriously.
[most]Americans want it done fast instead of done right.