Really, I started out on Japanese parts. They’re pretty solid. But my game actually leveled up markedly when I switched to Korean parts.
It does take a learning curve to get used to without the gates. But it was negligible for me. Maybe one or two days and my play was already good. Maybe I’m biased, but give me a Myoungshin Fanta and crown buttons over a JLF, or even my previously favored LS-32, and OBSFs any day. That’s with every game I play. I also play Tekken and when you’ve played it on both, you’ll understand why the preferred hardware for the game is Korean.
And as far as SF4 plinking goes regarding the sensitivity of Korean parts. Yes, crown buttons are less sensitive than OBSFs, but they are far more sensitive than my previous Seimitsu buttons. I have zero problems plinking or anything on K-parts.
Actually, my accuracy in inputs is markedly better on Korean parts. For whatever reason, I was not doing hazanshu cancels from crouching position in SF4 on Seimitsu parts. I would get accidental inputs, including ones that would instead net me SBKs, I have never had an accidental SBK on a Fanta.
So yeah, maybe it’s biased, but I definitely feel Korean parts are better.