So, my reaction (heh) after a week — I still love the feature and think it is basically a “table stakes” level thing that should be enabled everywhere.
However, on meta, I have used 
more than anything still, because I’m generally not responding to things that shock or anger me and not everything is a party.
I don’t think the set chosen is necessarily a bad default in general, but not quite what I’d pick for a technical site like this one. I’m not sure exactly what I’d want instead — more research is needed, I think.