1. The Smith writes a damn good old-school Dick Grayson; all wise-cracks and pluck.
2. The fact that this story is set at some point before Infinite Crisis, since we still have Dick Grayson as Nightwing, working out of Bludhaven and generally being a much happier character than he's been since... well, anytime in recent memory.
3. The brief character moment where we get inside Bruce's cowl and have him pondering his own aging and mortality. I can't remember anyone else except Frank Miller approaching this subject and this is nowhere near as heavy handed.
4. Like Bruce, I too feel my three-sizes too small heart warm when I ponder this image.
5. Speaking of blasts from the past, I love seeing someone writing Ivy was she used to be written back in the day; putting the nymph back in nymphomaniac.
6. Finally, I love how Smith writes Etrigan. Especially his rhymes, which are very fitting for how Etrigan is written in the Vertigo titles. Or any Etrigan The Demon story Keith Giffen or Dwayne McDuffie ever wrote.
I also love the concept of the book, which centers around Batman having to protect Poison Ivy from a vengeful Etrigan. Why? You'll have to read the book to find out. ;)