They look well made, but over all far, far to small for extended habitability. (beyond a few days) Looking at the basic model I see precious little storage room for food and water let alone medical supplies, clothing, or personal hygiene equipment.
At that price one could contract or build by themselves a larger living space with the necessary accommodation's for 4 people to bunker down for a much longer period of time.
(they also fail to detail just what the emergency power supply runs off of, and how easy it is to access/refuel)
Here's the best underground shelter U.S. manufacturer that I've found. When I get the money I'm getting one of these shelters ( www.disastershelters.net/shelters.php ). For the cost of a small home. You can even have additions added on. Check out the Swiss vault door. I would probably just live down in it most of the time anyway.