I spent this past weekend, Thursday through Sunday, touring 25 layouts as part of of an NMRA regional convention. And while there wasn't a 3 rail O layout in the lot, I feel a greater connection to that group than to the collector / toy group that most people tend to associate with 3 rail trains.
It was very interesting to see that even among 2 railers, different aspects of the hobby were favored by various people. Some layouts were super detailed with relatively simple track plans. Some people were serious prototype modelers with layouts designed to be operated by large crews.
When you get down to it, 3 rail scale, is just model railroading with an extra rail.
Next time the NMRA regional comes to town, I'd like have my layout on the tour.