I don't plan on building my family shelter out of these, but I do plan on using them extensively starting next year. Here's why.
Price is cheap, less than 3K delivered. Use your tractor to put them where you want them. My plan is to dig a long trench, drag them into it, and fill them with stores. They are watertight, air tight, and dark. I am going to attach a nozzle/vent to mine so I can fill them with Nitrogen or CO2 depending on cost.
What can you store? Fuel, tractor, ATVs, electronics, food, water, ANYTHING at all. Temperature controlled by the ground, an 8x40 unit has over 310 sq ft of usable floor, and over 2400 cubic feet of space. That's a lot of storage.
You could easily weld tanks in place that you can fill/extract from at the surface, as well as create a ladder entry to better conceal the way in and out should you need to go in for supplies. Don't forget to vent the inert gas inside or use scuba gear to go in and get what you need.
Another use: Bury them in the ground with the top at ground level, cut the top and put windows in place. You then have an inground hidden greenhouse that can grow low light crops. Alternatively you could put solar panels in place and use growlights and hydroponics. I won't be using them for growing anything illegal, that would be stupid. I'll be using them to grow beans, strawberries, potatoes, etc. Expensive? Not too bad if you can do your own excavating and you understand the way to make it structurally sound.
Ground pressure will collapse the sides or top if you're not careful. This is bad if you're storing in it, but deadly if you're living in it. Think carefully about the weight of the soil around it and use steel/wood to re-inforce it as need be. Just a few interior walls and well place beams would do wonders regarding wall strength.
I'm considering building a house with these. For the price of a double wide you can have a 2,400 sq foot house configured any way you want. That's if you can weld, work with wood, and do your own interior. Make sure you learn about water barriers, earth walls, mold issues, etc. There are HUNDREDS of things to consider when building any structure.
This site will help you get on your way:
http://www.containeralliance.com/buyers-guide.php