Some people may ask why I suggest you to buy Japanese Card/Booster/Theme Deck instead of the English one, I can tell you at least 4 reasons:
Reason1: It got better paper quality.
If being placed in cool condition, holo card starts to warp thanks to the different expand coefficient between paper and aluminium based foil. For those English card it curves like a macaroni. Althrough same problem occur in Japanese card, but the degree of warping is negligible.
The surface finish of English cards are much rougher than that of Japanese Cards thanks to those low quality recycled paper. The only advantage of such high degree of curvature is that you can cheat easier :)
Reason2: It worths
For each booster boxes you've opened you can get holo pokemon as well as EX-pokemon 5% more easier. With comparatively cheap price :P
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Reason3: Greater looking
According to my personal research, many players don't like the yellow border of the card, the white border of Japanese one seems more popular.
Reason4: Its legal
Its legal to use Japanese cards in the current POP format, if that card is already released in US. Feel free to use them in tournaments, but don't forget to bring the translation/reference with you.