I love dogs far better in real life, but not in Animal Crossing. Nintendo seems to make more wacky, themed cats than dogs. For example, there's Tangy the orange, Ankha the egyptian, Kubuki the japanese, ect. The dogs tend to be just general colours but not themed.
I'd love a dog villager. Isabelle is cool but she aint enough. I currently have two cat villagers, one of whom is Katt who I actually like a lot, the other being Olivia who i'm more than happy to trade for a dog at some point.
Irl I'm a dog person but in animal crossing I don't have a preference. My only dream villager that's either is Marcel the dog, but that's only because he resembles a clown/mime.
I think Nintendo kind of shafted dogs in Animal Crossing anyway. There's cats with really cool themes and the dogs are mostly just.. Dogs.
I don't know if it's just because I was looking at Stinky, but I think the cat villager models look a bit strange in New Leaf. They look a bit too lanky for me.
That said, I've never seen a villager dog in-game, so I can't really compare. I guess I don't really have any preference otherwise.
Cats, they are cute and fluffy and simple adorableness. I like dogs but they slobber everywhere, bark alot and are super hyper running around and you cant really cuddle with them. Also most of the time I find they smell bad but all in all I like both but prefer cats more at the end of the day.