I don't get the fad with circos plots. At least in genomics, they offer a high density of information but unfortunately at the price of hard if not impossible interpretation. Like the systems biology papers of old, showing beautiful dense graphs, but with little room for biological interpretation. In addition, circos is quite... peculiar as an application, in particular its quirky configuration file format, which is half ini like and half XML or HTML like. Last I looked at it, about a decade ago, there weren't any APIs to create plots programmatically.