N.B.
I am an Iams cat parent all the way. The Original blend only. Tried others (hairball kind, etc) when my cat was younger and they just made her barfy more.
We adopted a fat fat cat almost 2 years ago and she came with Science Diet for overweight cats. She was lethargic and a bit blah. She started eating the other cats food, so we just continued with what we knew and shes shiny and happy and playful! Still fatty fat, but thats OK.
So Iams all the way for us.