Hello /an/, catfood question here.

I used to feed my cats crappy purina food from the grocery store because I was poor, stupid, and uneducated. Now that I know better, I went searching for good food that can fit in my budget and I found Felidae. The ingredients on the back sounded great. So I bought a small bag and did the whole mix a quarter new food with old food, then half and half, then three quarters new with one quarter old- that whole deal. Well, now that the food is mostly Felidae, they sort of pick at it and primarily go after the purina bits still left in there. When I put a piece of purina and a piece of Felidae in front of them, they go after the purina. I have two cats- one male, one female. The male seems to be growing a taste for the food, but my female still doesn't seem to care for it too much.

Should I try to find a different food for them (is eukanuba any good)? Should I just switch back to crappy purina? Should I continue to try Felidae? Ugh.