It's hard for me to tell, really, the intelligence comparison between cats and dogs.
I know that cats have a natural instinct to kill, whereas dogs are a little more subject to their environment.
The cat doesn't often reply to things that dogs do, such as tricks and such, but I don't see that as mark of intelligence, but rather interest.
Dogs are lot more welcoming, unless trained otherwise, whereas a cat is not welcoming at all until they are familiar with you. In general. It's something that can't really be 'black and white' because some cats are very welcoming, whereas some dogs are not.
From what I understand, dogs are indigenous to coyotes and jackals, and their relative is the wolf.
Cats are indigenous to the big cats, pretty much tied altogether.
So both have quite a wrap sheet on intelligence, which makes them great pets, so in my opinion, I'd say they are about the same in intelligence, just different interests.