A few years ago my cat suddenly had problems and no longer adjourned its existing feed. Vet wormed etc, but the problem remained. A colleague recommended me Pro Plan, and that has (previously also like her) "saved" my cat. His digestion becomes normal, since no more complaints. I feed it now for about two years, and he eats like it too (otherwise picky and interested little for food).
10 kg is very convenient, is enough for 4-5 months at a bowl dry food a day.