I live in one. It was built by the previous owners (literally...not contracted out). Ours is a stand-alone house without an attached shop/barn.
Regarding durablity...ours is about 4 years old. We've been here 2 years, so I can't speak for long-term, but I love living in it. We have a much bigger and nicer than we could have afforded in a traditional home. The maintenance is practically zero. Our energy bills are suprisingly low.
Hello! We would be happy to talk to you about your project. We are a custom barndominium builder here in the BCS area. We have an office and showroom for you to come see our work and discuss floor plans. Please feel free to give us a call!