Just wanted to say I found the CH threads on Katz's very helpful in preparing me for my first pastrami sandwich there. London sandwiches are nothing compared to NYC's.
It was actually my first pastrami sandwich ever. I went with hubby, baby and sister. Hubby headed straight for waiter service seating so I had to holler at him to sit elsewhere. The place wasn't too busy (weekday late afternoon) and had a mix of locals and tourists. Each counterman had only about 2 people waiting in his line. I chose a counterman who looked sort of old and world-weary. The counter was quite high (I'm really short) and I sort of had to jump up and ask for a lean pastrami on rye with mustard. I didn't want to look stupid waving a dollar bill above my head (I'm sure if I were taller I could have nonchalantly held it in my hand in the counterman's view), so no tip incentive apparent but the man still cut several pieces for me to taste. I was holding a piece out to my hubby to try and get him to taste (he was too embarrassed: he isn't as enthusiastic a chowhound as moi) and to my surprise the man in line behind me popped it into his mouth and said 'that's good'. I was a bit shocked and the guy shrugged and said 'hey, your fella wasn't interested!'
I remembered to ask for a pickle. When the guy handed down the tray, it had the sandwich and a plate with about 6 pickles on it. I had to slam dunk the tip into his cup. That counter is really a bit too high. I had a Dr Brown cream soda as well. Hubby had a sweet potato knish, ice tea and insisted on having fries. Sis had chilli dog and capuccino(don't ask, her eating habits are a mystery to me). A few tables of locals were chowing down corned beef/pastrami. A trio of Japanese ladies were seated around a single pastrami sandwich, delicately nibbling away at bits of meat picked out from it, after they had photographed the sandwich from all angles. A guy in a suit and tie, wearing latex gloves disinfected his table and seat with alcohol wipes before eating his sandwich.
It was interesting and the sandwich was great. I couldn't finish it. I've attached a photo.
Thanks, chowhounds, for directing me to Katz's.