You would to draw a more specific line on what you deem to be a dog and what you deem to be a cat - not to mention what better means. As for domesticated (canis lupus familiaris) and domesticated cats (felis catus) there is no question: Dogs are better, and here is why: the domestic dog is a very1/5

Cats don't actually care about people, all they want is your food. They don't love YOU, they love your FOOD.

Dogs are more helpful to humans (saving lifes, assisting the disabled) resources given to cats would be better used helping productive dogs.