Comment by elliottwilliams

I've used both. The problem I had with ZD is that it uses a non-standard "ligature" (not sure what the non-coding term is) to identify zettels. This means lock in not just to emacs, but to a specific package. Org-roam OTOH uses standard org-mode notation, which means I can freely mix deft with org-roam or any other package that plays nice with org-mode.