The Silver Bullet For Clean Water?

Popular Science magazine is reporting on an invention that might have huge implications for water starved areas of the world. Well, maybe not water starved, as it doesn't really create water. Vapor compression distillation machines can filter out clean water from just about dirty water source: sewage, seawater, polluted river water or whatever, or so the inventor claims.

They've already deployed the "Slingshots" to Africa. They're looking to spread them around even further with the help of the Coca Cola Company. I'm surprised this hasn't gotten more press, or did I miss it?

I'm wondering how effective they are with seawater but, more importantly, how much do they cost to buy and operate? Current desalination technology makes it pretty much the most expensive way to get potable water. If these machines are more efficient and less costly to manufacture and operate, might this be the silver bullet we've been searching for to make desalination practical?