What is Evaporative Cooling?
Evaporative cooling is the method of converting hot air into a cool breeze using the process of evaporating water. Similar to the cool refreshing effect you feel when you immediately step out of a pool, it is nature’s most efficient means of cooling Evaporative (or Swamp) coolers utilize the natural process of water evaporation along with an air-moving system to lower effective temperature by up to 15 degrees under optimal conditions. Fresh outside air is pulled through wetted filters that cool the air through water evaporation. A blower wheel then circulates the cool air throughout a desired space.

What are the pros and cons of Evaporative Cooling compared to Refrigerated driven AC's?

Are evaporative coolers more suitable for specific climates?
Although swamp cooler systems work best in dry areas swamp coolers will work sufficiently in just about any hot location where there is a fresh supply of air such as an open window or door.  However, it is important to take this factor into account when choosing between a refrigerated A/C system and an air cooler.  If you reside in an area that is very dry and arid such as the MidWest, then an Air Cooler would be an ideal, cost effective choice over an AC.  On the other hand, any tropical - humid environment or location would not reap the full capabilities of an Air Cooler and an A/C would be a viable alternative. Remember, these units add moisture to the air as part of its cooling process so if being operated in an enclosed area, it will continuously increase indoor humidity levels. This is something that would counter-productive to overall in indoor comfort especially if you are located in an area that already has a high level of moisture in the ambient air.