First, we live in Arizona which is a desert with very low humidity. Evaporative coolers work best in these environments and not in high humidity places. But even so, this has helped cool the back bedroom down making it not only livable in the heat but actually cool. When the monsoon season starts and the humidity starts to rise, I expect it not to work as well. We have 30% humidity or less and it will take 80 degree temps down to the low 60's. I recommend using filtered water to keep unpleasant smells from minerals in the water to a minimum. Also, let it run dry with the fan on to dry the filter out about once a week to help with this issue as well. This is normal maintenance for an evaporative cooler.
I use distilled water and it provides cold air on my face. It does have a light bar when turned on but I covered it with construction paper so I could sleep.
I use this Air Cooler on my boat and in my office. It really does cool you off if you are right next to it. It's designed to cool a small space. Very happy with it.