Cats are sooo much easier. They go in their cat box - which is not smelly - and will only eat if and when they're hungry. We've been able to leave for a couple days with the cat at home and perfectly fine. You can't do that with a dog.
Cats are easier to care for (as long as they have no behavioral problems). Cats are independent, where as dogs need discipline and exercise by means of daily walks. However, both are loveable to the max!!!
Dogs can be a handful, but if you train them with discipline, then they will eventually know. Honestly, cats tear stuff up with claws and are ANNOYING when they go in heat. Like, they sound like a baby howling. Cats most likely wouldn't respond respond to their names. Dogs (in my opinion) are more loving and are more of a snuggleupagus. X)