Here's my problem with those cup style drinkers. You see how they had it inside the run with all the wood shavings on the floor? Those shavings, poo, and other debris will end up in the cups just from the chickens being in there scratching and pecking and running around. This will lead to increased maintenance by the owner.
Also, those cups are designed to fill up and hold water. Depending on where you live, freezing will be an issue. I already mentioned my setup has a heater inside the 55 gallon drum (I have enough birds that I need this size container). The heater has a thermostat to keep the water inside the drum from freezing, but the water that collects in the cups outside the drum would freeze and prevent the chickens from drinking.
I'm not saying you shouldn't try them or that type of setup, but for my location where we have winter, I did not have the best experience with that.