It was absolutely packed when we were here, and that was on a weeknight.
The fesenjaan is good enough to command that kind of crowd. It was really, really good. It comes with a nice side salad, famous Persian rice, and yogurt. I'd order it again 1000 times over. The Persian tea was also quite good.
The bademjan appetizer, however, was charred to the point of tasting burnt. I don't know if it was a fluke, but it was not right.
The service was prompt, but verged on condescending at points. Still, the fesenjaan makes this place worth a visit!