Taiwan. I think the Japanese generally are much better at creating depth and subtleties of character, and the same is true for Hana Yori Dango. But I personally like the Taiwanese version better. The ML and FL are both hotter. They make the ML super angsty and fiery like he's supposed to be. .. kind of volatile. And their aesthetic and sense of style is just so superbadass. Taiwanese dramas from back in the day didn't ever have a lot to work with as far as budget. So their sets and effects can be kind of hokey and silly. But their clothes and hair, the general look and feel they're trying to achieve with their sense of style is so on point. Even now you could watch it, and there's a distinct lack of tragic clothes and hair in their version. UNLIKE every other version of BOF.
Also Hana Yori Dango was sort of targeted at a slightly younger audience than the Taiwanese version - In HYD, the punch scenes are goofy, and the ML is goofy (in acting, style AND looks). In the Taiwanese version , everyone plays it straight up, no bullshit. That's more to my tastes.