It depends on how you define intelligence, really. And since you are comparing two species that do not communicate in a consistent way with us humans, how would you go about determining that intelligence? It can't be done (sceintifically). Unless you believe in size of brains, but craniology was dismissed over 100 years ago.
Also, animals are just like people (we are all mammals) some are smart, many are average, and some are stupid. But we can't really tell without careful observation of the creatures in their environment, not ours. Just because we can train a dog, doesn't mean a cat is dumber, it's not in it's natural environment. But from the human perspective, cats are cute playful things that do nothing other than poop in a box in your house. A dog is man's best friend.
All that being said, my dad has a dog that he does not treat like a dog, it is a member of the family. Total we have 3 dogs in our house and they all live like people, they sleep where they want, they go out when they want, say what they want, and they eat at the table with my dad, and we never try to subordinate them with dumb commands like sit or stay, we just take good care of them, and let the dogs be what they are, dogs. They are all smart in the sense that they pay attention to what people do, and the female watches my dad all the time, and she pays attention to our language, and reacts to many words. She always listens when you talk to her, she understands most of the time and behaves unless she is distracted with chasing a cat or something. But this is an atypical situation in most households, the dogs are truly treated as people. Which brings me to my final point, all dogs like to think they are people.
Dogs rule.