Hi Juliana,
I sat with this question for about a year and a half before making my decision. I didn't know what was worse - design qualms or paper quality.
I chose the US versions to buy because of the additional goddesses and gods included, which are meaningful to me and because of the revamped design of both the card backs and colours. However, I didn't know if I'd hate the decks when they were actually in my hands due to the paper quality. And I have to say, yes, the quality IS thin but I like the decks nonetheless, I shuffle them easily and that's about it. I just treat them like thin decks that are not to be shoved around or thrown into my bag without a box. And yet, they haven't warped at all.
What helped my decision making was that I had bought the US version of the Oracle of the Shapeshifters due to the fact that Aus version to me, was full of design inconsistencies and card image lifting. I was upset. And even though the US version had this same thinner card stock, I love the US version. (I know that they've rereleased the Oracle of the Shapeshifters Aus version and I'm guessing it was for these reasons I've mentioned?) My point is, the thinner card stock is different/thinner but the deck images are so much more consistent and that's what matters for me above all.
I hope this helps with you with your decision and working out what's most important for you too!