Yeah, my enjoyment of Myth may have been due to nostalgia, but I still think it's still a great series.
It also still has a active community, though that may equal about 100 people. They still create mods, and there are some online games happening every so often. They work pretty hard to keep the game playable with different OS.
There is a demo (two campaign maps, a few multiplayer maps) that is compatible with the mac and windows computers at http://tain.totalcodex.net/search/?x=0&y=0&q=demo&for=any . I would recommend the demo to anyone.
If you enjoy games with story, you would probably dig it. It shows where bungie got their great storytelling skills.