I'd prefer use of notes. However, as far as I can see, notes are not copied by the default fetch rule:
[remote "origin"] fetch = +refs/heads/*:refs/remotes/origin/*
AFAIK the reason that tags are copied is that they refer to commits that are reached from the heads. The easiest way to propagate a global set of notes seems to be to have them in something like "refs/heads/notes/commits", and configure core.notesRef accordingly at the clones.