Building a steel home?

We are looking at our options for building an inexpensive home. We have seen advertisements for the steel home kits, but are unsure of how to do something like that. We want to spend our money on several acres and building a large home, without a lot of frills. If you have done this before, can you tell me if it saves much money, compared to building a traditional home? What problems should we be aware of? Energy efficiency? Durability? Any information from somebody with experience in this area is appreciated.