Just one data point, but I had never heard of transit or edn before today. Both look awesome.
On the other hand I picked up YAML in less than a day (many years ago) and despite its complexity can't remember that ever causing me any issues. Not 100% sure if missing from your suggested formats (which do support multi line strings) but I enjoy use of yaml's folded strings.
On the other hand I picked up YAML in less than a day (many years ago) and despite its complexity can't remember that ever causing me any issues. Not 100% sure if missing from your suggested formats (which do support multi line strings) but I enjoy use of yaml's folded strings.