I loved 'em both back in the day. Slightly off topic, CN is killing it right now with Adventure Time and Regular Show. They both seem to be aimed more at the twenty-something 90's kids like me (and probably a lot of you). Wish Flapjack was still around.
People ask me this all the time. It's really hard to answer. Shows like "Courage the Cowardly Dog", "Dexter's Laboratory", "Ed, Edd n Eddy", "Johnny Bravo", and "Billy and Mandy" vs. "Rugrats", "Jimmy Neutron", "Rocko's Modern Life", "Hey Arnold!", and "Catscratch". I think I'm going to give Cartoon Network a SLIGHT edge, just because I like their classic stuff to Nickelodeon's classic stuff, although Nickelodeon had some pretty badass stuff.