Trees I hunt I'd be seriously limited with a ROS. Very few pole shaped trees, so I usually have a limb or two in the way, preventing me from moving around the tree. Might be waist high, might be head high, but either way, it's hard to move. The platform lets me turn around as much as needed, so I don't have a weak side shot.
Having said that, I may invest in a ROS before next season anyway, to take in when I know the exact tree I want to hunt is suitable for it. The tree I was in for my last sit this year is a perfect candidate for that.
I'll always take the platform instead if I'm just winging it.