Look, they're both great, but Donald has the advantage of generally being a good guy beneath the anger. Its funny to watch him fail and get frustrated and cathartic to see him pull through. Daffy doesn't really have that heart of gold aspect to him, so his successes are mostly jokes that he's somehow winning despite (or because of) being Daffy. Basically, Donald has more range.
Disclaimer: As a card carrying Ducktales 2017 fan, this post is heavily biased.
