Many Kosher Lower East Side delis have gone out of business, but Katz's is a survivor. There's nothing special about it - basic Jewish home-style and deli food in large portions. All the pastrami, matzoh ball soups, and latkes that gentiles love too.
Besides the place staying in the family, I think one of their secrets has been NOT to change. We've all seen popular little old funky places decide to expand, renovate, and go upscale. And then go bust.
Katz’s Deli, secrets behind keeping a 130-year-old business alive