Depends on the make and model, the noise is high, I have a big air cooler the size of 270l fridge that cools the entire floor, it runs during the day and it drops the temperature from 32c to about 28c, but if feels like 26c because the vapor evaporates on our skin.
Its useless in night or when humdity outside is already high. During which time I revert to air conditioners, which on average consume twice as much power as the air cooler.
A good air cooler should have a less then 21c air temperature at the fan vent, it still no match to a air conditioner which has a air coming out at less then 6c.
Low humidty in air conditioner rooms increases chances of getting cold or other viruse related illness.
High humidty like in air coolers, lessen chances of getting cold or other virus related illness but increases bacterial growth or illness also corodes electronic components.