I grew up in the 90's, so in many ways, the DCAU Superman was the version of Superman for me. Full disclosure: I have only really read JLA, some of Loeb's run on Superman/Batman, Byrne's Man of Steel, All-Star, FAS, and some random issues of Action here and there. I constantly hear people say that the DCAU Superman didn't really act like Superman. Dwayne McDuffie even mentioned that the Superman he was writing in JLA had a different personality than the one he worked with on JLU.
So how exactly was he different? Who is DCAU Superman compared to the Superman in comics? What did the creative team "miss" about his character?