swamp cooler v.s. air conditioner

Should you buy AC or a swamp cooler? First of all, swamp coolers are about 30% cheaper to buy. Swamp coolers might be louder in some cases, but they are also much easier to service. Also, the cooling costs per month are much lower. Which is better for the enviroment? Swamp coolers are actually much better for the enviroment than air conditioners. so, which should you buy? I would prefer swamp coolers any day.