Benjamin, not a bad article, but it doesn't really address the merits of bladders v. bottles (or even spend much time discussing dehydration).
If my understanding of the literature is correct, under ideal conditions (not too much food, not too much exertion) your stomach and small intestine can take around a liter an hour into your system. Drink any more and you'll just pee a lot. It doesn't take much heat and exertion to respirate and sweat far more than a liter of moisture out over an hour.
I say because I think that the vast majority of backpackers spend much of their trips hydrated beneath the level of optimum efficiency, but are working at a level sufficiently moderate that it doesn't matter.
Bladders and hydration hoses make it easier to sip water and thus hydrate ideally. They also place the heavy water close in and centered in the pack.
In summary, horses for courses. In the mountains in the summer I carry bottles, because it's cool, I don't need to carry much water, and I can fill up often and quickly. In the desert, where carrying a gallon of water is routine, a hydro system is the only reasonable option. In winter, where surface water is often non-existent and water has to be either melted or gathered from isolated sources, I'd like to be able to use a hydro system, but unless you can wear the bladder under your layers near the skin (which a backpacking pack precludes) I find bottles the only practical option.
