My First Knish Ever...

For all my Jewish friends: I tried my first Knish ever today and had the hardest time deciding - should I pick the plain potato one or a sweet one but in the end I settled for the spinach and potato one. Was ok, but a little bland. Not sure if cheese or something wouldn't have been better. So next time I guess...
This is a wonderfully old fashioned place on Houston Street and it even has its own merchandising products so I am assuming it's famous?