It´s true that not all brands are the same. Here are some things to look for.
Things to Consider:
Type of Meat – Cats need protein. When reading labels, you need to look for a specific protein source, such as "chicken," and avoid labels that generically say "meat."
Chemical Preservatives – Do your best to avoid foods that use chemical preservatives like BHA or BHT.
Variety – To keep your cat from becoming too finicky, you should switch up his food every so often. Give him not only a mixture of soft and dry food, but different flavors and perhaps even different brands.