Hi I have 3 jills (Females) yes they do smell a bit which is why people tend to keep them out in the garden or shed in a hutch, also getting the hobs (males) castrated makes them less smelly . they are very friendly and playfull and would make a great pet for a child although when young they can be a little bit nippy and when they bite if you pull back they clamp on and the more you struggle the harder they bite so be wary of this with children but if you don't struggle after a second or two they just get bored and stop biteing.
You can house train them they will always do there buisness as far away from there sleeping area as possile so you can train them to use a littler tray, but I suggest if you are going to keep them in your house you get an indoor cage for them so that you are not falling over them all the time they get everywhere very quickly and also they are safer shut away when you aren't home, you can also train them to come when you call them.
A small tip, get them micro chipped they are little devils for escapeing 2 of my three have at some point over the last 6 years made a break for it and the RSPCA do check ferrets for chips thank god I'm so glad I did it, also jills need to be spayed other wise they go in to season and don't come out again unless mated or given an HCD injection by your vet if neither of theses happens the jill with get Aplastic aneamia get very ill and possilbly die. good luck with your decision let me know if you have any more questions i might be able to answer. :-)