I bought the 3L cup for my rabbits! It's really good especially in the summer when they drink a lot more. It's annoying because it's not completely full and it's harder to fill it because of its big size. Very good! The problem I have is just with refilling water.
This water dispenser is great. It is filled from below. Should be kept clean from the inside (limescale deposits). If you understand how the dispenser works (pure physics), you know not to tip it over! The water runs out to the front if there is no water in the shell. So turn it round ;)