Automatic cat feeders are designed to make feeding less of a chore. They come in different sizes, styles and with various features. Cat feeders can be used for a single cat or multiple cats. If your purpose of having a cat feeder is to free feed your cat, any style of feeders will do. However, if you want to regulate your cat's diet, you can get one that allows you to set the amount dispensed and time of feedings.
The disadvantage of cat feeders is that they can only contain dry food since wet food is a lot more perishable and cannot be left out in room temperature for long.
Some people may consider an automatic cat feeder for their cats if they will be away for a long period of time. Cats are very smart animals.
Never underestimate their ability to get what they want. You maybe surprised to know that cats can easily learn to sneak food out of anything once they know where the food is located and how it gets out.
I would not replace a human pet sitter with an automatic cat feeder for that reason and also having a person play with the cat everyday will greatly help relieve some of the stress induced by your absence.
It may take sometime for your cat to get used to a cat feeding machine and understand what it is for. The video below will give you a very good idea of how cats may react to an automatic cat feeder for the very first time.