Sanwa are the default for Japanese-style buttons, and they're the most common at all levels of play. If you don't know what you want, they're probably the best place to start and with how modular sticks and hitbox-style controllers are, you can always change down the line if you find that you have different preferences. Personally, I find Sanwas just a bit too light for me since they'll accidentally actuate if you brush up against them. It makes it difficult to rest your fingers on the buttons and it's a bit harder to "ride" the actuation point, if you're the kind to do that.