It depends a bit on what you want to optimize for, as there’s drawbacks to all the major methods:

• Ultrasonic sprayers are decently efficient but spread any contaminants around your home, potentially still biologically active. Dissolved trace minerals will turn into fine dust, affecting cleaning needs.
• Boiling for humidification is energy intensive because of water’s heat capacity.
• Air forced wicks are by default great habitat for mold and similar, so they need regular care and replacement.