With Retort, it’s flexible. One person can post multiple reactions to a post. And since it is separate, you can “like” independently.
With the new Discourse-Reactions plugin, one account may only react in a single way at all. You can’t even “like” and also mark another reaction. If you use another, it replaces the “like” (or whatever other initial reaction was marked)
EDIT: if you are asking about the choices for which emoji are available, I think Retort has option to be limited or to allow anything, and maybe the new Discourse-Reactions requires specifying a limited set?