i had a 36" port-a-cool fan for my 2400sq foot garage in texas. According to my thermometer, the air coming out of it was 16 degrees cooler than the air going into it. Doesnt sound like much, but when it was 101 degrees outside and your fan is blowing 85 degrees, it makes a difference.
It would have worked better if the air in east texas wasnt so humid. The port-a-cool has a different media than a swamp cooler and has much more airflow and cooling capacity.
I wouldnt recommend one for the house though, unless you kept your windows open. Since it gets the cooling effect from evaporating water, it will raise the humidity in your home. And the more humid the air, the less cooling it provides.
http://www.portacool.com