Got into Vegas around 10 or 11 at night, and came here for the midnight munchies. There was a wait even at this time, but it was reasonable.
The pastrami sandwiches here are HUGE, as mentioned by other Yelpers. My boyfriend claims it was the best pastrami sandwich he's ever had, and he's clamoring to come back. Very very good and one of the good value places in Vegas to eat at. Their cheesecake is also delectable. Definitely stop by here when your stomach and your wallet needs a break from fine dining.
*** update 3/27/08
I had to take off 1 star for service this time. The bf had a craving for pastrami so we came a little around 1 am. The servers were unfriendly, a bit understandable for 1 am, but I was disappointed. I also ordered a potato knish, which is huge. Yummy, but perhaps you'd want to share. Picture above.