I wouldn't even go to their kosher branches. At least all religious Jews stay away from the treif ones. But on the other hand, at least if they are kosher, non-religious Jews are less likely to sin.
I liked Burger King and Kentucky Fried Chicken but they are no longer in Israel. Burger Kings all became Burger Ranch so Jews are now banned from Burger King except for the one kosher one in Costa Rica. Pizza Hut now operates in former KFC brances. They are owned by the same company, as is Taco Bell. I wish they would have all 3 in Israel.