Domestic Concentrated Solar

I've recently come across this site advertising a domestic scale concentrated solar hot water system. There's a suggestion that this is the first domestic concentrated solar system on the (US) market. The suppliers claim the increased efficiency over flat plate or evacuated tube systems gives payback up to 3 years earlier, under US conditions. I'm not sure exactly what their methodology is, and I have no desire to do any number crunching myself. However, I have one comment: our own flat plate system is more than adequate for our needs so a more efficient system would only produce our requirements more quickly which makes me think that in our case, if we were trying to choose a system right now, the deciding factor would be capital cost.