Mine get Science Diet. I like to free feed, as I believe it's healthier for them. JD won't touch wet food (strange kitty), but he likes Tender Vittles once or twice a week as his "treat" food. Elvis likes Fancy Feast, which I also give him maybe once or twice a week as a treat. He likes the chicken flavors best.
I don't give them any people food, except a little bit of tuna when I open a can, and also when I go to the fish market, I get 4 large shrimps, one for each of my babies. I just boil the shrimp in plain water, no seasonings and give one to each. Cats and turtles love it!
The turtles eat a variety of fruits and vegetables, pretty much whatever I buy for myself, they get some, plus about once or twice a week, a few pinches of turtle food pellets for protein. Yertle loves to steal a few bites of cat food when he thinks nobody's looking. Bad turtle!