Years ago, I made ladder stands out of 7'6" 2x4 building studs. There were dozens of them laying around the building lots, after the houses were framed. (apparently carpenters don't like "bent" wood?) I'd climb up, set my butt on the platform, and shoot deer. Never gave much thought to cover, or even how high I was. Basically, I could see as good (maybe a little better?) as if I was standing, but I was sitting and more comfortable!!! About 10 years ago, I bought a 15' ladder stand. 1st time I climbed up in it, I just couldn't get comfortable... (Ok, I was shaking like a dog passing a peach pitt) I only hunted out of it a few times after that. My big problem these days, is that my back starts to nag me, after about an hour of sitting. On the ground, I can get up and stretch and move around if I have to. It helps to keep me in one "spot" longer. If you're in a good spot, I don't think it matters if you're on the ground, or in a tree, or how high you are.
Just one old farts opinion...