I sell both Japanese and English Pokemon cards, and I've handled thousands of each. Ask five collectors which is "better" and you'll get five answers, so instead here's what I've observed with the two side by side — physically, financially, and in what buyers actually do.
Print quality: not a myth
The Japanese quality reputation is earned. Centering on Japanese cards is visibly more consistent — when I sort incoming English lots, off-center cards are a routine find; with Japanese lots it's the exception. Japanese card stock also differs [describe: the layered construction/texture differences you notice handling them]. None of this means every Japanese card is perfect, but if you're buying with grading in mind, the starting odds are better.
The price gap
The same card in the same set frequently costs [X–X]% less in Japanese. Part of that is supply — Japanese sets print heavily — and part is that the biggest collector market for English cards (North America) treats English as the default. The gap is not uniform: alt-arts and trophy-tier cards can flip the premium, and cards featuring characters popular in Japan behave differently. This gap is the entire reason my Japan import pipeline exists.
Pull rates and god packs
Japanese sets have historically offered better hit rates per box, and some sets feature "god packs" — packs where every card is a hit. That changes the economics of ripping product versus buying singles: in Japan, singles prices reflect the better supply of hits.
Which grades better — and which sells better graded
Better centering means Japanese cards earn top grades more often. But here's the seller's paradox I've seen in my own sales: the North American market often pays more for the graded English card even though it was harder to grade. [Your observation — what actually moves faster/higher for you.] Population counts matter too: a rarer top-grade English card can beat a common top-grade Japanese one.
My recommendation by buyer type
Collecting for love of the cards: Japanese, no hesitation — cheaper, better made, and the art is identical. Grading to sell: Japanese cards for grade odds, but check what the graded comp actually sells for in your market first. Investing long-term: [your take]. Selling like me: both — buy Japanese for margin, list English for reach, and know each market's rhythm before committing serious money.