Edit: RouteGadget link, with analysis
A route-choice heavy Ultralong Championship course at O' in the Oaks 2013, Pacheco Pass. Almost every single leg in the entire course had several distinct route-choice options.
My strategy at the mass start was to take the first few controls steadily, at my own pace, and not let other people influence my route choices. It worked pretty well, and from control #5 onwards, I lost sight of the other people on my course and could run my own race.
The well-designed courses had a lot of really interesting route choice options, and I will post a RouteGadget link with some analysis as soon as it is available.