I'm puzzled by all the bad reviews... I find Katz's deli sandwiches quite moist and delicious. Never dry nor chewy.
My personal favourite is pastrami (on rye with mustard) because I love the extra seasoning and spice. It's subtle but you can definitely taste it. With a side of fries and gravy, that's a fine lunch indeed.
Struggling with which meat to order? The lady at Katz's described them this way: "corned beef is mild, pastrami is spicy, smoked meat is sweet". Not exactly sure what she means by "sweet" but I've also had the smoked meat and it's quite good as well.
Note: closed on Sundays.