"We purchased the medium sized feeder for our two cats. Although the small size would have been fine for cat food, the medium and large sizes have a food agitator to stir the food tank. We've used the feeder for several weeks now and have had no problems. Our cats no longer pester us to get up in the morning for breakfast, which was the main point of the purchase.
The timer for the unit is a separate piece that plugs into the wall, and the feeder plugs into the timer. If you plug the feeder directly into the wall, it would just run continuously. The timer also has a power socket that is always on, so you don't lose the use of a wall socket.
The feeder releases food fairly slowly, but it's not a problem with the timer. We release 1/3 of a cup at each feeding, which for us means running the feeder for 30 seconds. The unit is so quiet that the loudest part is the soft click of the timer activating.
Overall, construction is good. The base is made of thick, sturdy plastic. The tank is very solid as well, like a Nalgene water bottle. My only complaint is that the lid is easy to crossthread and can become stuck, but otherwise there are no problems at all."