The only way I will endorse the purchase of small animals is if the owner is sure to have plenty of time to play and care for the animal. Too many get all this love and attention until the owner gets board and then the little darling is locked in their cage until they die, with only eating and pooping as activity.
Have you ever had a small animal? Guinea Pig, hamster, etc....
Small animals are time consuming. I am not particularly familiar with ferrets but I would assume they are the same as any other small animal.
Just a few thoughts.
They do smell more than most animals but I think people just get used to it.