I'm not too familiar with the HKS, but with the Blitz DSBC you essentially get 5 settings (off, and 4 settings). If by easy, you mean changing from boost level to boost level, I think it meets your requirements. You also don't have to guess what level it is at because you would have preset the settings and know what boost you're running.
Like Ron Popeil says: "Set it, and forget it."
