Yes they are smelly, similar to otters - theirs is the fishy version as they are both mustilids. It took me a while to get used to it with my first boy but now I don't notice it. Most people get them desexed as soon as possible as it does reduce the smell. The Latin name for ferrets translates to smelly little thief and they live up to it.
Having said that they make adorable pets for the right owner and are usually kept in pairs or more.
They can be microchipeď which is a good option as they are explorers that can get in really small places, my first boy is currently missing having dug under the fence.