I would say that Lemongrass is ok, not great.
I've had the Panang curry a few times and really enjoyed it. The Green curry is also decent.
What brings Lemongrass down is incredibly slow service. Whether it's during a busy time or a slow time, it's slow slow slow. One waiter for the entire restaurant and that's it.
The atmosphere and ambiance of the restaurant are nice. And given the price, it's not a bad lunch spot.