Works great. Left it outside for my two barn cats and it kept them fed for a week while we were on vacation. I used the plug (110 house current) and installed the batteries as backup. Glad I bought it.
UPDATE: I have used this all winter to feed my outside cats. (It was kept dry under an overhang). It worked just great. Large hopper holds several weeks worth of food (depending on your cat's appetite) Even during our too frequent New England power outages, it transitioned seamlessly from plug in to battery mode with no loss of programming. Extremely dependable. We recently had a nighttime visit from a skunk. The critter knocked the feeder off the porch, down seven steps and onto the concrete walkway. By the time I found it, the top and bottom parts were separated and the feeder tray was knocked off. Despite this abuse, the hopper remained intact, latched and securely closed protecting the food. I simply stacked the pieces back together (a very simple operation) and the unit worked perfectly without missing a feeding. This is one of the best purchases I've made on Amazon. Definitely worthwhile investment. Highly recommended.