IMO, it largely depends on style of hunt, length of hunt and types of trees.
If you're walking for hours with no idea where you may set up, a ROS is hard to beat as ounces count. Conversely, if you're walking a few hundred yards at most to a known area with known trees, a platform is more comfortable.
For me, a ROS is only comfortable for 2-3 hours. After that, your feet start to hurt. Others may have differing opinions as my only experience is with the Bullman Apex.
For trees, 99% of my trees are cantelope to basketball sized. For that, ROS placement at 3/6/9/12 are plenty. With a platform at 6, a ROS at 12 is great as it helps moving around the tree.
In short, I really want to like the ROS for all hunting situations as it's lighter and gives greater maneuverability. However, I can only do 2-3 hours before my feet hurt from them and a platform feels fantastic after using a ROS. The happy medium seems to be a platform with a single step 180 degrees from the platform. Wider trees may require more steps but the trees in my AO aren't that big.