Unless you are just getting the deal of a lifetime--steppers, ellipticals, and treadmills are all three some of the worst use of space and money IMO. Much better workouts available with much less financial/space requirements.
As has been said on other threads here, steppers do not give you any training on down steps which are just as, if not more important to train than the climbing. Training only uphill will create muscle imbalance and not have your musculoskeletal system as prepared for the downhills you will face.
You can get yourself in much better cardio and muscular shape with a kettlebell than you will with any of those machines. A simple, varied kettlebell routine combined with some weighted rukking and/or actual stair climbing (with descent) will have you where you need to be without having to buy/store a bulky machine.
YMMV
EDIT: I withdraw the "deal of a lifetime" caveat

There is literally no scenario where I would pay for or store a cardio machine in my house.