I bought one of these about a year ago and am now buying my second one. The second one is to provide multiple feeding stations, to allow me to thoroughly clean one while the other is available and to allow alternate food on occasion.
My review is based on me using this with ducks not chickens. This feeder requires training so if you have a large turnaround in your flock, it may not be the best for you. I don't know how well the trained birds would train the untrained birds. If your flock is a fairly stable flock once the birds are trained, it just works.
Here is the normal training and how I had to change it for ducks...
Step 1: The feeder is bolted completely open. This allows the birds to see the food and know that is where the food is. They walk up on the plate and eat the food.
Step 2: The feeder is bolted halfway open. This still allows the birds to see the food and know that is where the food is. They step on the plate, it goes down to the ground and the lid opens. This will probably startle the birds at first but they get used to it and will eat the food. With ducks, this doesn't work quite right. They figure out they can not step on the plate and stretch out their longer necks and eat out of the half open feeder. I bought a length of PVC and a sheet of aluminum and made the plate twice as long as the original. This way the ducks could not stretch over the plate. This required me to put a 1 lb. weight on the lid to offset the weight/leverage of the new plate.
Step 3: The feeder is allowed to fully close. The birds can't see or reach the food directly, but if they step on the plate, they will open the lid and they can eat the food. If you get 1 or 2 birds to do this on day one, the other birds will join them on the plate and within a few days all the birds should know how it works by themselves.
Step 4: I put the plate back to its original size so I don't have any confusion when I get my second one.
In my case I had to put the feeder in a deer proof enclosure and I haven't had any other animals eating out of the feeder itself. The ducks do spill a little food eating out of it, but they with the help of the occasional song bird keep the area clean so the rodents don't have much of a lure.
I have 12 ducks and this holds enough all flock to feed them for 2 - 3 days. We top it off every day and because of the way it flows the food, it gets the oldest food eaten first. It is inside a pet gazebo (to keep the deer out) and if it rains or snows with any wind it will hit the feeder. The food stays dry. In the winter I might have to clear the snow from off the plate and under the plate, but the food is well protected. I am sure between songbirds, squirrels and mice I have saved well over the cost of this feeder in food plus I am not exposing my flock to the possibilities of disease that having these wild animals feeding constantly would create. After 1 year, the feeder looks the same as the day I bought it (well maybe a bit dirtier) so even though I have seen other feeders that work the same way made out of wood, I decided to shell out the money again for a second one. I would guess there is no better endorsement than that.
An unplanned consequence of using this is since they have to go into the gazebo and operate the feeder, it is a bit more of a hassle for them. As a consequence, they would rather forage then eat out of the feeder which means for the most part they eat first thing in the morning, and just before they go in the house (when they are hungry). There is an occasional nibble during the day, but probably not as much as they would eat out of an open bowl. That means my flock are staying (so far) at a healthy weight even though they have food available all day and I don't have to supervise feeding times.
Edit: 12/22/16 This is still an awesome feeder but I wanted to throw a warning out there. We now have two feeders (and 15 ducks) and there is the occasional day that they don't eat enough from either feeder to make a noticeable dent. Probably due to foraging in the summer, or too darn cold to bother in the winter. Every day we check both the levels and the kick plate operation (in case it should freeze). But after 3 days in a row of no noticeable eating (they were getting additional C.O.B. by hand to fatten them for the winter so they did eat something), I inspected the operation more thoroughly and found that about 1/2" of snow had built up on the ground under the kick plate and that was enough to limit the lid lifting to about 1/3 normal height, not enough for a duck to easily eat out of. So I cleared the small amount of snow and there was a 5 minute feeding frenzy. No harm done. So because of the leverage from the plate to the lid, a very small change in the plate motion made a very big difference in the lid motion. I still strongly recommend this feeder, both feeders are like new at 1-1/2 and 2-1/2 years old exposed to the elements 24/7. It keeps the food absolutely dry, uninfested and uncontaminated.
Edit: 1/9/2020 My feeders are reaching the 5 year point. They are no longer in a gazebo, they are in the ducks' pen. They are good as new (although the finish is a bit dull now.) This was a very sound investment - absolutely recommend it!!!
!! Sorry.. that was from my nesting box review... don't know how it got in there!