I have mine on Wellness. If you have an older male neutered cat you want to keep the ash content down in his food. High ash can cause crystals and block the urine. This causing the kidneys to fail. Purina is high in ash. Just something to watch for.
I switched my cats to Innova and California Natural (from Science Diet). Boy have I noticed a change in their coats. Andrew my 14 year old was starting to matt. He is shorthaired. I assumed it was because he wasn't grooming well. It has been 4 months since I switched and his coat is beautiful! It is shinny and soft where it was dull and flakey before. I swear by the stuff. My 9 and 14 year olds get Innova Senior and the 2 year old gets California Natural. I love the stuff and so do they!