Used the 4 Apex steps this weeks over a 5 hour sit. They're small, light, easy to setup, quiet and are at most comfortable for about 2 hours.
When leaning, their tapered angle can cause your feet to slip to the edge and cause pressure points on your feet (and I was wearing boots with a composite shank) that made it painful by the end of the hunt.
That said, they stuck to the tree well and made it easy to move around the tree and remain stable in any shooting position. If I had no idea where I was going and expected to be doing alot of walking along with packing out any meat, I'd stick with the ROS. For shorter hikes into a known area and long sits, I'll stay with a platform.