Both are realllly different.
I had a cat for 8 years. Was ok, its cute but doesnt do alot of things. And you dont have to spend hours with him everyday, he will sleep most of the day ^^
Few months ago, i received a dog for my birthday. Idk if its cause hes just a baby, but its alot of work! But soo much fun then a cats. The dog is human best friend is true. You dont believe it until you have one.