They're very different!I'd have to say they're even more expensive in terms of ongoing care than something like a large parrot,which may sound absolutely insane.It's all to do with the food though,since even high quality parrot food will be much cheaper than something you could safely feed a ferret.It takes a strong stomach too due to their dietary needs,at the very least!
Once you get past the whole diet problem though they're wonderful little killers,despite the adorable and seemingly innocent face
As for smell,that depends on what the ferret in question is fed.Of course,any ferret will have a musky smell as that is just generally the scent they produce,but an extremely good diet does help.Of course,ferrets being fed on poor quality foods(the majority of ferret specific foods,with a few exceptions that could work in a pinch)are going to have more odor for various reasons.