As for maintenance and/or troubleshooting, I would hope the developers would have taken this into consideration and have a plan plan for it. That would be a huge selling point.
Of course, the most important thing about this would be the price to install. It does say in the article that it this would be more affordable than currently available products, but that doesn't tell us much. If the cost to install is not proportional to the money saved from buying electricity, then what's the point. It would be like buying a hybrid vehicle just to save money on gasoline. Sure, it gets better fuel mileage, but if you ever have to replace the battery, it more than wipes out any savings in fuel you've realized.