A/UX is a fairly old AT&T based Unix implementation. It allows you to use a Mac like desktop, which is largely compatible with Mac software and has MacX to run X software. It also offers a straight X11(R5?) front-end.
The Unix end has at least one nice extension: a Commando interface that allows you to issue Unix shell commands by pointing and clicking. Even though it is annoying for regular use, it is a quick way to learn how these commands work and which options are available. If you want to see Commando in action, it's also available for MPW (a free download from Apple). Apple also provides compilers to keep developers happy. And lets face it, programming environments were one of the big reasons to use Unix systems back in the day.
The Unix end has at least one nice extension: a Commando interface that allows you to issue Unix shell commands by pointing and clicking. Even though it is annoying for regular use, it is a quick way to learn how these commands work and which options are available. If you want to see Commando in action, it's also available for MPW (a free download from Apple). Apple also provides compilers to keep developers happy. And lets face it, programming environments were one of the big reasons to use Unix systems back in the day.