Cathy's is a big improvement over Danny's Deli (who used to own it). Food is very good and plentiful. I like breakfasts there best of all. If you get a sandwich, make sure you ask for some garlic bagel chips, too. Yum yum.
Pros: Great service, nice friendly people, Cathy is very sweet and the place feels good there.
Cons: I've had much better deli meats in more traditional kosher places (like Juniors or Cantors in LA). It is the best deli in Santa Clarita though by far.