I can sleep just about anywhere. I am out like a rock at the drop of a hat and usually on command, whether crammed into the back seat of a car with three other people or in the flat seat of Club World. It's quite useful, being able to sleep wherever and whenever.

But who ever said there is less oxygen coach/economy??? I don't think that has much basis in fact, and it makes little sense. Different airlines have different class configurations, and I seriously doubt they modulate oxygen output per cabin. The media would have a field day if that were true.