I don't know it well Jodie, but I'd recommend asking the question in the instructor's forum. You'll get a much better response I think. Let us know what you end up with.
I think Peak chairs are sturdy and simple. They are very user friendly. There are not many options for resistance changes so somone who is very heavy or very weak may have a hard time using them.They are stackable so they are easy to store. They look less intimidating than other chairs.