I'm on team CSO because I think the steam-bake and steam-broil functions really bring something new to the cooking toolbox. I don't have a BSO so perhaps it's capable of many things my wall ovens (which have a dehydrator function, but not airfryer functions) do not.
One thing to consider is that the CSO has a steam vent which should not be situated directly underneath a cabinet when in use so you need to either have some vertical space above the vent or the ability to pull it out while running the steam functions. This only a concern on steam. You can toast, bake, broil or warm plates with no worry.
