Very good. The art generally looks nice, but I sometimes find it hard to distinguish characters without context (readers of my reviews will notice a theme here). Still, I was interested in the story - it was nice to return to the Buffyverse after so long.
The thing that really make this book, though, was the dialogue. Joss scripted, so the characters' voices rang true, with a few very funny lines that felt just like they were coming out of Geller or Brendon's mouths. Also, the in-jokes.
Not the same as watching the TV series, but pretty close.