Standing up and staying tight to the tree isn't a problem in the M100U, sitting down your a little farther away than the m25 but not by much. Just hang it in a double trunk tree.I can see the M100 would be more comfortable with the back support but how much does it hinder you if you need to stand up and stay tight to the tree? Also, how far does it keep you out away from the tree while sitting compares to a stand without the back? I like to stay as tight as possible to help with concealment.