On the surface, they're not much different from living on Earth. They harbor self-contained environments and emulate living planetside as much as possible.

However, there are differences. If you live in a colony, you need to know where the nearest emergency shelters are. The spaceport is a large part of everyday life. And last but not least, the colony has to be treated with the utmost care in order to keep all of the inhabitants safe.

But a lot of the randomness of nature here is nonexistent. Bodies of water are much safer and weather is predetermined.

[Like everything else, living in a colony has its advantages and disadvantages compared to living on Earth. Athrun figures neither is inherently better, and that it comes down to a matter of personal preference.]