Both Humidifiers and Vaporizers work equally good at putting moisture in the air.
The only real difference between a humidifier and a vaporizer is that the humidifier puts out a cold mist of water to add moisture into the air.
And a Vaporizer heats the water up first and then lets it off as steam which can be better for colds and congestion.
The humidifier is great for when you just need to add moisture to the air and don't need warm moist air due to having a cold or flu virus or having congestion which makes it hard to breathe.
Humidifiers are better for when you just need to moisturize the air when it gets dry and the vaporizer works much better when you need more hot steam coming into the room which is much better for colds, congestion and the flu.
I have both a humidifier and vaporizer and use the vaporizer when I have a cold, flu or congestion and then use the humidifier when I just need to add moisture to the air.