I've bred working ferrets almost all my life.
As long as they are well bred, well reared, constantly handled and you know what to expect from them, they make fantastic pets and will generally get along just fine with a dog....although I'd still keep an eye on them, just incase!
Unfortunately, one thing I wouldn't recommend is keeping them in the house. Yes I know there are people who do so and those same people will try to convince anyone that their ferrets don't smell. To be honest, I quite like the musky smell of 'eau de ferret' but not everyone does. ALL ferrets have this natural odour, which any truthful visitor to the house should be happy to confirm.
Also, as previously mentioned, Jill (female) ferrets will need to be brought out of season at least once every year. Although not something I would recommend, this can be done by most vets with a Jill jab. My preferred option is to use the services of my vasectomised hob (male).
AL