I have the C4 ladder on my 4Runner. I got it 100% for aesthetic reasons and have really only "used" it to help dry off the car after a wash. My only complaints (not specific to this ladder) are that it's relatively close to the face of the hatch and doesn't leave much room for your foot to physically fit, and it does limit the width of things you can hang out the back window.
I love the way it looks - it matches my roof rack perfectly - however it's much easier to actually reach the rack from the side. I typically stand on the tire or the sliders to get up to the rack. If you're looking to actually climb onto the rack and stand up there it would be useful in that scenario.
As mentioned, I don't think I would trust it or any hatch ladder if I were a heavier individual...