As Daddy_Duck mentions in the description for this RMS, it is a NOmad version of Ensemble Studios' Unknown script. It generates completely random maps. You will get everything from islands to arabia to medi maps when playing, you just never know what kind of map will be coughed up.
Theme: Well, the idea is somewhat borrowed of course, but the whole Unknown aspect of ES's map translates well to NOmad. Exploring these maps with three villagers really means something each and every game because they really are new and odd each time around.
Visual Appeal: Given the crazy random nature of these maps, they aren't usually very handsome. There isn't too much that can be done about it, so if you're looking for pretty stuff, you've come to the wrong place.
Playability: Being truly random maps, there is the chance that you'll run into a bug or two. Having a villager trapped in trees happens on occasion, and I think I even lost a ville to a Jaguar on one map. On the whole, the maps that are generated are quite well suited to some NOmad fun, with a good spread of resources and villagers.