I know you've already desided but I wanted to come in with my 2cents.
I prefer ferrets to rats (not something you usually say on a rat forum but oh well!). Well socialised rats are more licky, and being small and rodents they do smell less and have less maintence, but they don't live long.
I've found baby ferrets are insane with their constant running, but they do bond to their ppl. Tazz does a lap around the room then spends the rest of the time trying to get me to chase him. He will dance up to me, open his mouth and start butt scooting backwards. Ferrets are definate clowns! I usually say picture a hyper-active kitten, and thats a typical ferret. Some are cuddly, and Bear used to lick me, and yes Squirrel was an ankle biter (but only cause she wanted me to sit down on the floor with her to be at her level).
If smell is a problem get a single ferret, often shelters have ferrets that for some reason don't get along with others and need to go to a single ferret only home. As long as the bedding is washed weekly and the litter pan is scooped daily there isn't alot of smell (assuming that your not keeping them in a teensy room that is, it would be more noticable then). Try an air filter with a carbon hepa filter insert. The poo does smell bad, unlike cats they don't bury it but they are litter trained. As long as you don't let it sit around its fine. Because they are carnivores food only stays in their digestive tract about 4 hours. To cut down on smell give only a high quality high protein food. The better the food the less they need to eat to meet their nutritional needs, the less poo in the pan. Also avoid any foods with carbs in the first few ingredients(not good for them), or fish (any fish makes them smell sooo bad).
Also bathing too often makes them produce more oil which gives them that musky smell. Unless they are dirty they don't need to be bathed more than a few times.
Its like having a cat or dog, they need daily play time, at least 2 hours, but this is easy. I have Tazz out when I'm vegging infront of the tv. He steals the dogs dinner, checks in with me every 2 minuites and has a blast with his toys and tubes. I have him in a ferret nation cage, plenty of room for 2-3 ferrets. Most of the time they all jam into a single hammock
Ferrets sleep alot to make up for their antics when they are outside.
They need yearly vet visits and vaccinations, but if your lucky you have a friend for about a decade.
