Don't really see how you can compare cats and dogs. They're so completely different, so really it's just personal preference, not which is better as an animal, just which is better for you.
I love dogs for sure. Love hiking with them, love driving around in the car with them, love getting into puppy wrestle fights with them, love snuggling with them, and love teaching them tricks. But...I don't like the maintenance that goes into a dog. You can't go to the same beaches anymore. You always pretty much have to plan around your dog. "I can't, gotta go home and walk my dog, but I'll meet up with you later."
Love cats, too. Yeah, lots of them are pains in the bum, but so many have amazing personalities. My last one was a total snuggle bunny. I clicked my tongue and he'd come running. He'd sit in my lap while I was on the computer, and when I went to bed, he slept right next to me, wrapped in my arms like a teddy bear. My current cat? He's more like a dog, so the perfect balance. He sleeps on top of me. Whenever I get out of my car, he runs out to greet me and follows me. He goes with me to my boyfriend's house. He loves riding around in the car. And he knows sit.
Obvious pro's and con's to each and no two dogs are really the same, just like no two cats are really the same. Ask anyone who lost one and then a little down the line gets another.