Schwartz has some very good smoked meat, that has to be said. I wouldn't say it's the best I've ever had, but it is definitely worth going. The fact that people wait in line for so long is a testament to its quality.
On the other hand, the aforementioned waiting time is too long (it feels like trying to get into a packed club) and the service is terrible, which pretty much ruins it for me. They will pack you inside wherever they can, and nobody really pays any attention to you. I understand that they are always extremely busy, but I'd rather go to a different deli where i can actually eat comfortably...