More expensive doesn't always mean better. Hill's Science Diet is probably a pretty good pet food. At different times with the six cats that my husband and I have, our vet has recommended this particular brand of pet food. Once I did bring some home from the vet's office and my cat turned it's nose up. Some cat's may love it and eat it with no trouble, but mine won't.
If you are one of the ones that your cat will eat it and you feel better about giving your cat this food, then be prepared to pay a little more for it than you would Purina or Meow Mix. For instance, you can only buy Hill's Science Diet at certain retail stores and your vet's office. So when choosing a pet food, you may decide that based on how available something is whether you will use that product. You can buy Hill's Science Diet at Pets Mart, Pet-Co, and Care-A-Lot Pet Supply. All of these places have websites to order from as well if there isn't a store in your area.
As I said before, price is another issue. For instance, a 3.5 pound bag of Hill's Science Diet costs about $13.99 according to Pets Mart's website. Meow Mix can be purchased practically anywhere. Your local grocery stores, Wal-Mart, and Dollar General sell this product in a 3.5 pound bag for $4.99. A 17.5 pound bag of Hill's Science Diet will run you about $38.99 compared to the same size bag of Purina Essentials that costs about $8.99.
Now, to me, a cheaper cat food that can be found at almost any store in America is more convenient and a better value. Like I said earlier, my cats really don't like the more expensive brands, Hill's Science Diet included. There are plenty of great cat foods available out there. Mine eat IAMS. It is not as cheap as the some of the above listed, but it is very reasonable compared to Hill's Science Diet. It is also more readily available than something that can only be purchased from a vet, a pet store or on-line.
When picking out a cat food for your feline companion, you should make sure it is something they are going to like. It should also be as I have heard others say digestible to them as well. You should pick something that fits within your budget. Let's face it, not everyone can afford higher priced foods. You are going to have your feline friend with you for a long time and shouldn't you want to do all you can for them? We all do. But as I said, more expensive doesn't always mean better. For me Hill's Science Diet isn't worth the extra money and the extra running around to get when my cats don't like it anyway.