Daffy. He’s got a bit more character to him. Donald just gets angry at the situations he is in whereas Daffy’s overconfidence will get himself into hilarious situations for him to rage at.
Easily Daffy. I thought he was hilarious and still to this day, I say phrases from his cartoon dialogue. My wife is kind of clumsy and trips over everything, so when it happens, I say, "So, it jumped out in front of you?" Besides Donald being one of the core original Disney characters, I never liked his undecipherable incoherent ramblings. He just seemed mad all the time without substance.
He went from a funny crazy duck to a butthurt jealous asshole with the ego the size of Montana whenever he feels Bugs gets more attention than he does. IDK, maybe it's just me.
I like both, but if I absolutely hafta choose, I'd go with Daffy. He's got more character and is a bit more cunning.