- Fundamental bug in the way they compute message schema checksums used for compatibility checks, causes buffer overflows and undefined robot behavior when changing array lengths. Is marked as wontfix because they don't want to recompile existing packages.

- custom build tooling based on cmake is super cumbersome and buggy, and it means that you simply cannot communicate with ROS based stuff, without yourself becoming a ROS module that uses that custom build tooling

- there is no QOS, messages are retained somewhat due to the topic semantic, but you can't tune retention parameters or resends