The ending contains a twist with something akin to shock value. Was it great? It depends. Part of my issue with how things play out is having a good idea where the plot is going long before the final scene with the guilty culprit. Here's a small hint — this person practically sticks out a hand and says hello. A scene with Stella (Melina Kanakaredes) and Danny (Carmine Giovinazzo) clarifies exactly who, as long as one is paying close attention.
Flack is apparently back to his old self. I'm guessing the warehouse incident ("Pay Up") is chalked up to an all out assault on the no-goodniks, and so no cop is charged who fires a weapon. Danny probably could have some suspicions, since he charges down after Flack does his dirty deed. Then again, this is television. One is required to suspend disbelief from time to time.
The live music from the group Train is a delightful touch. It's worth watching the episode again just for that.