How is it not lights-out? You could remotely power on/off the servers (XServe only). Other Macs could not do this, as they did not have the separate LOM network interfaces, etc.

I managed a bunch of XServes for a while, they were incredibly good hardware. The Mac Server software kinda sucked (not the LOM stuff, it was as good as any of the LOM from Dell, which is to say, not amazing, but workable).