Both Barbour and Chiles believe that large-scale systems are vulnerable to human errors and thechnical malfunctions that can cause wide ranging consequences. They also both agree that technology is a new "unknown territory" that can either make society and the world a better place or it can destroy it depending on the path we take towards improving it.
I found that Barbour seems to focus on environmental concerns and social aspects in regard to technology. While Chiles focuses on how technology can "go bad" do to human error and lack of understanding.
In the end they both try to point out concerns we should pay attention to.