I hope it isn't a sign of my dislike for the main characters, but this was by far the strongest issue of Sirens so far. In fact, the few scenes where Poison Ivy actually appeared, I found myself as annoyed by her as I always do. I like Catwoman, but Harley and Ivy have always seemed really foolish to me, so this issue focusing on the Riddler was quite fun. I liked the dueling internal monologues from Batman and Riddler as they initially face off too. Riddler deciding to just play along as if he didn't know Dick was Batman was a great piece of characterization, as was Dick's thought that Tim Drake/Robin is a much better detective than he is. The murdering team of villain-wannabes is a fun idea that I'd love to see more of, even if the leader does use one of the names of a hero I created years ago (Conundrum). She was a fun, entitled character that will make a good recurring villain.
Guillem March's art is still titillating and exploitative, but I found myself less bothered since he had to spend most of the issue drawing the guest-stars. He couldn't get by with pinups and cheesecake, and I think the issue looked better because of it. His take on Batman is pretty darn cool.