I've only had dogs. Dogs are awesome, especially when you take the time to actually train them...some people don't deserve dogs.
My only interactions with cats as pets has through friends and a neighbor's cat that adopted me I guess. They were alright. I don't think a lot people actually know how to train cats and you end up with the ones who kind of just live in the house with you and do whatever you want.
I prefer dogs but wouldn't be opposed to having a cat. Had a schnauzer that was kind of cat like.