I think it really depends on the individual animal - but it general, I would say cats are (slightly) easier. You don't have to worry about leaving a cat home alone too long - they have litterboxes! There were days that Sassy would be home alone for over 12 hours, and she was perfectly fine, and I didn't really feel guilty. I can't leave the dogs for more than 8-9 hours, and I feel guilty if it's over 6 hours. Cats are easier to exercise - a couple quick sessions of playing with the laser light or the feather pole and she's good. The dogs need a lot more exercise, much of it outside, in the heat or the cold or the rain or whatever. Cats are cheaper - cat toys cost less than dog toys, cat treats cost less that dog treats, cat food costs less than dog food (since she eats significantly less than the two dogs), etc. My cat is easier, behavior-wise - but again, this is going to depend on the individual dog and the individual cat. Sassy has really no behavioral problems - she doesn't scratch inappropriately, she uses her litterbox, she's fine with strangers handling her, etc. HOWEVER... My cat is a picky, picky eater. She'll eat a select few kinds of canned food, and a few kinds of dry food - and she highly prefers the dry food. She won't eat supplements/medications disguised in the food. And this frustrates me to no end. Missy will eat anything that's given to her, and Jack, at the very least, likes things that are good for him (raw, canned, meat, cheese, fruit, veggies) even if he won't eat dry kibble or hard biscuits. And he'll eat any supplements/medications if you mix them in canned food. The cat looks at you like you're trying to poison her if you try to feed her most things. This is the only way that my cat is harder to deal with than the dogs.