Astro actually lives with a cat, but isn't truly trustworthy around cats. He has yet to hurt one, but I don't doubt that he would if he were unsupervised. His housemate is my roomie's big male cat, with claws, found on the street as a stray in NYC. He's a tough cat that doesn't back down or run.
Astro has been around that cat since he was a little puff-ball puppy. Through a ton of work, Astro will be called off a cat and disengage, he will listen to "leave it," he respects the babygate that separates his half of the apartment from the cat's half. But still, I've made my peace with never having a cat after I've moved out of here in September, because he's gotten corrected by multiple cats, and all it does is drive him on to crush the poor thing. A running cat is a chased cat. A cat who is completely neutral and friendly and sweet will still get grabbed around the neck if I'm not there. It's part of the reason I'm so, so, so anal retentive about Astro's whereabouts: he's either with me, being watched actively on his side of the babygate, or he's crated securely behind a closed door, period. No roaming in the apartment allowed. I consider my roommate's cat to be my priority as much as he is hers, since I'm the one with the bigger, more antagonistic animal, so I make sure there won't be an accident.
Honestly, being cat-friendly is very, very low on my list of priorities, generally speaking. I had hoped that getting a young puppy and socializing it to appropriate behavior with a stable cat would stack the deck in favor of having a cat-social adult dog, yes. But I'm ok with the fact that it hasn't worked out, and my roommate is ok with it too given the level of vigilance I keep up. I'm allergic to cats and don't feel the same pull to own them as I do dogs. As long as a dog can be proofed to listen to "leave it" when walking down the street and a cat crosses the path, I'm cool.