I personally find Tom and Jerry far better. Much more diversity. There are some shorts where they work together, some shorts they reconcile at the end, both lose at the end, some of them Tom wins, some Jerry is the malicious and others it is Tom.

For Tweety and Sylvester they seem to mainly be the same, Sylvester wants to eat Tweety but keeps on failing.

Tom and Jerry! Even though I haven't seen as much of Tweet and Sylvester as I have of Tom and Jerry, based on what I have seen, Tom and Jerry is the best.

The episode where Tom died and went to hell scared me so bad when I was a child

Tom and Jerry. The others are far, far less entertaining.

Tweety and Sylvester.

Tweety and Sylvester. simply because I LOVED Sylvester as a kid, while I always found Tom and Jerry pretty exaggerated in everything they did and with their violence...

Tom and Jerry.

I still enjoy watching an episode or two on good occasion.

Tom and Jerry FTW! They have a love/hate relationship where no one is the good one or the bad one. Honestly, both of them are a pair of a**holes.

In Tweety and Sylvester the bird has to be the "good" one, but it's so annoying that you just want Sylvester to win.

In my opinion: Tom & Jerry > Road Runner & Coyote > Speedy Gonzales & Sylvester >> Tweety & Sylvester.

Tom and Jerry by a country mile. However, I didn't like those... racially insensitive stereotypes on a handful of their cartoons.

Tom and Jerry. That and Bugs Bunny are for me still definition of TV cartoon show.