I am posting from England, I think that is the same as the USA - we mostley have derailleur gears.
But I am unsure in what way Sturmey-Archer gears are different. Sturmey-Archer are mostly 3 gears. Are they more for slower pased riding?
Over here most Sturmey-Archer gears are on older bikes for sale on ebay. Maybe the compact nature of Sturmey-Archer makes them better for folders?