I agree with everything
@EricS said above. The only things I would add are I have found the WE aider more forgiving then the knaider for step spacing. There have been a few times when climbing with the knaider that I couldn't place the step exactly where I needed to because of a knot/limb, etc. and if I placed the step above it I couldn't get the knaider hooked on. The adjustability of the WE aider helps with this.
Also, I never use the WE aider when coming back down. I simply squat down on the step I am standing on, grab the step that is at chest level (waist level when standing) and lower myself down to the next step. It's surprisingly easy.