I can only refer to the meeting notes: https://openehr.atlassian.net/wiki/spaces/spec/pages/2201812993/2023-11-15+16+Arnhem+SEC+Meeting
Search “@Pablo Pazos introducing ADL3 is also an opportunity to “switch” to other serialization format…”
There are mixed opinions, I guess because of different experiences and use cases. What I remember mentioning in the meeting, that might not be in the minutes, is that for JSON there is a schema, which is more convenient for validation, though there are some adaptations to use JSON Schema to validate YAML, and there is certainly a simpler JSON ↔ YAML conversion than XML or other standard formats to JSON.
Before making any decision, we (SEC) should consider use cases, pros and cons of each format. Though my personal preference would be not to have one single “preferred” format, but instead having a standard serialization and deserialization process to/from many formats to the AOM 1.4 an 2.x, that allows then to have bidirectional format transformations like format1 → AOM → format2 (change format1 and format2 to whatever you want). That way we can support multiple use cases. For instance, if I need to display an archetype on a web app, I would prefer JSON because of the browser’s native support for JS. For storing ADL I would prefer YAML because it’s smaller. So using the best format for the job.
+1 on the comment by @sebastian.iancu I don’t want to start a discussion on which format is “better”, just wanted to point out those formats were mentioned in the NL SEC meeting.