I don't quite get it. Is it basically a swamp cooler? Ie, trickle water down a filter medium of sorts to encourage evaporation? If so, that's 1) A really neat idea, it works well for greenhouses, 2) Hugely, HUGELY overpriced (which makes me think it must be something more elaborate than what I'm thinking - but the postage stamp sized picture at the site didn't really lend itself well for me understanding how this thing works) and 3) Expect your humidity to go up so have a plan in place to shed that humidity. I've been in greenhouses powered by swamp coolers and the humidity is basically 100% - not something you want in a house.
I'm going to have to see if I can find out more info. Tunze makes a similar product? I'll check there first maybe.
I'm all for a lower cost alternative to cooling though.