In my experience, hognose poop has the worst odor of any species I've kept. When I first got him I switched him to paper towel substrate and at only 11 grams I could smell his poop throughout the room. I actually remember thinking a neighbor may have fertilized because it honest to goodness smelled like cow poop. Since he's been moved to his bigger enclosure he's on aspen and I only notice it if I open his enclosure. Thank you substrate for absorbing the odor!!!
I've never had stinky corns or Kings though. I've moved on from corns, but will always keep Kings. Django's poop has pretty much no odor at all.
My BP, Tyson, has some stinky poops, but not always. His pee stinks like hell though.
I honestly don't really remember how any of my snakes pee/poop smelled years ago when I was first keeping snakes, but don't remember any that were real stinky.