Manny Hattan's (sp?) is pretty good. In general I just don't like a sandwich that has 1.5 inches of meet stuffed in between 2 small pieces of bread. I mean most bits you are just getting meat. That is not a great mix. Ah Jeez just realized how bad this post is already sounding.
The only reason I hit up Katz's while in school was because it was open 24 hours. In hindsight, I should have just went to Taco Cabana.
I think their food is pretty good. And, I like the energy of that place. Although it's a "New York" deli, when I'm in there, I think "it's great to be in Austin."