good thing about cats is that they dont make your whole house smell like shit.
I have both:
My dog is nice, I can play with him but he has so much energy that sometimes he gets very annoying.
My cat is fine too, he seems to enjoy sleeping on my clothes which always leave a huge amount of hair on them and he doesn't seem to really care about me. BUT, everytime he bails while running or bails while trying to jump on something, it's fucking funny.
Therefore I can't really decide.