The Good
Two words: Joker and Snyder. Heck, let's make it three and throw in Capullo. This is exactly what we would want in the return of the Joker.
Thirteen is definitely a bad luck number for Batman. Since the New 52 started, we haven't really seen Joker. The big question is what happened to him since we found out his face had been cut off. How and why this could happen has been a mystery as well as what has he been doing since.
Scott Snyder is a versatile writer. He has wowed us throughout this series. There's no arguing his knack to generate a dark and creepy atmosphere in his comics. That vibe along with Greg Capullo's pencils and Jonathan Glapion's inks makes this the dark and twisted comic we would expect. As this is the beginning of the major Joker story, Death of the Family, there's really only one chance to do his reappearance after being absent for so long. We have seen many different versions of Joker over the years and Snyder and Capullo gives us the perfect one. There may be some questions or doubts about characters in the New 52 but there is no doubting how vile and flat out evil Joker is. Capullo perfectly captures the tone for Joker's grand entrance. If this is what the rest of the arc will be like, dealing with the Court of Owls will pale in comparison.
There's also the size of this issue. There is more to the story than simply Joker returning to Gotham. There is a lot that happens here. Having the story span in different settings adds to that. Joker's entrance is brilliant and lasts several pages but the story far from ends there. We get to see plenty of the reactions to his return as well what his next move is. You can feel the ties to the original Joker stories. Using those stories as inspiration to define Joker along with amping him up with a new level of despicableness shows just how Snyder's mind works. He is able to take an old and familiar character, update him in a great way while still making the connection to who he was when first created.
Having a fantastic back up dealing with Joker and a certain other character by Snyder, James Tynion IV and Jock is the icing on the cake. This further illustrates what goes on in Joker's mind. Obviously we don't fully enter his mind, nor would we want to. We do get to see how twisted and cruel he can be. Jock's style may differ quite a bit from Capullo but seeing a different side to part of a scene gives a set of chills only Jock could deliver.
The Bad
This is off to an incredibly dark beginning. That's exactly what we'd want from a major Joker story. Don't look for an uplifting story here.