Credit to Tudyk for pulling double duty on Joker and Clayface, but he can't cackle like Hamill.
It's not even a comparison.
Not because any of them are bad, but because each Joker is in a different scenario. Tudyk's is a part of the Harley Quinn series, which is more about comedy than anything(also his Clayface is great).
DiMaggio features in the Under the red hood movie, which is very dark and I think his performance fits that.
Hamill is from the older animated series but he also shows up in the justice league series and a few movies. I'm not really old enough to appreciate him in the cartoon but I liked him in JL.
Someone also mentioned Kevin Richardson and he's probably my favorite. He's from a later animated series and his version of Joker is much more random, crazier.