My 2 cents. O scale 2 rail requires enormous space id you want reasonable curves. What 3 rail folks call 072 is an overly tight curve for 2 rail.
I have (had) a 2 rail switching layout built up with atlas flex and peco tight radius turnouts. A great way to learn the limitations, track work had to be perfect. Any imperfection was painfully obvious due to the wheel flanges.
That being said i had the opportunity to visit Ed Rappe's model railroad, it is nothing short of spectacular, i imagine an operating session would be equally rewarding. Same goes for the trolley layout built be the owner of micromark. 3r especially high rail affords some of us the opportunity to get close to the level of 2r but the cost and space constraints limit the market penetration.
And to close, because i had the time this winter i was able to build and populate a HO switching layout for about $150, track, rolling stock, scenery. The same effort in oscale 2 rail would have presented a challenge.
