Although the technology is amazing (if it actually works), I think I'd rather stick with a combination of solar, wind, and geothermal on top of a greatly reduced energy requirement. (i.e. When it comes to the future of energy for daily living.)
For example, I think the
Passivhaus and the
ZEB are the direction in which we should be heading. It isn't about how much energy we can generate; its about
generation - (consumption/efficiency) = energy surplus/shortfall. Why rely entirely on a single (possibly dangerous) material for generation when there is energy all around us?
Anyway, you asked what I think, and this is it.
Edit: I think these small units might have applications for a transitional stage when we move from our old model to a new one. I think it would be good if we can learn more about its safety issues in addition to the overall cost of disposing them.