Choosing between refrigerative and evaporative air conditioning is a bit like having to choose whether you’d like effective or cost-effective cooling. Refrigerative cooling is widely regarded as being a lot better at cooling than evaporative systems, particularly in areas of high temperatures and high humidity - but it uses a lot of electricity.
Evaporative cooling uses a lot less electricity, but it's much less effective in high humidity areas, and if you're thinking about efficiency. It's important to remember that part of what you need to consider is the comfort it provides for the amount of energy used.
Fans provide yet another way of cooling, and are more cost-effective again over evaporative coolers. If you live in a humid climate, fans are the more efficient option between the two.
Refrigerative air conditioners provide much better cooling than fans, but can cost 30 or 40 times as much to run.