My cats also love Blue Buff canned food. And, other than the inclusion of menadione on the list of ingredients, it appears to be quite healthy. (And, there seems to be some disagreement as to the danger of menadione to cats in those amounts, anyway.)
It is my backup canned food, along with Chicken Soup, for when I can't get a hold of my new number one, Merrick's.
OTOH, they didn't care to much for Blue Buff dry, and left all of the "lifesource bits", which defeat the purpose of including the vitamins in the first place.