The Good: -The art is all to the good. The graphics and color are clean and appealing, and Hector Gomez (who's been out of comic-dom for about 2 years) does a better job overall (IMO) than does Joe Bennet, who works on the main series (at least when it comes to drawing the guys... Xander looks too old and grungy in the main series).
-Brereton knows the series, and the characters, and really has a lot of affection for them. Brereton's main passion is a series called the Nocturnals, which he both draws and writes script for -- so he knows the genre.
-Brereton proposes several interesting ideas in the Dust Waltz.
-Giles niece ('Death Wish Spice') was pretty cool :)
-Lilith comments that 'no good has ever come from one of our Kind feeding on a Slayer' -- she cites the Master's failure as an example.
-And Lilith can show up again later, which is all to the good :)
The Bad:
Plot holes you could drive Oz's van through.
-Lilith thinks that the Slayer is dead, but also knows that 'her son' the Master is dead. The Master was killed BY the Slayer, so what's the Flum? Seems awfully weak.
The Annoying:
I appreciate that Brereton likes the show, and watches it with his family every week, but I became increasingly annoyed by the constant show references in this story -- some is good, too much is TOO much -- it stopped feeling like conversation from the characters and started feeling like the author saying 'See? I know the show!'
Logic jumps with nowhere to land. Some of the characters (notably Giles' niece) do some things that had no support in the story.
The Summary: -If I sound overly harsh above, that's only because I /am/ being overly harsh. I admit that, and I think I know why: I'm used to analyzing a Buffy story line ad nauseum and finding it essentially airtight -- this works fine with the show, because JOSS analyzes everything for airtightness too. This doesn't work on the comics as well, because while Joss signs off on the concepts, he isn't involved with the story itself, so you get holes, logic problems, annoying character things, and timeline goofs.
Brereton ain't Joss, and he ain't never gonna BE Joss. I can forgive him for this, because he really did do a good job, and if he, like all the script writers for the show, had had Joss there to go over the story, his story would have been as airtight -- the fact that Joss isn't there isn't his fault :)
Because the book /is/ good. The story is solid, and presents some fun ideas, even if they aren't strictly canon. The art is great -- both accurate (more so in some places than the comic series, especially with Xander) and visually exciting. The only problem I had with the Big Monster is that there wasn't ENOUGH of him -- Brereton /did/ do a good job of telling a legitimate Buffy story that we HAVE to see in a comic, because we could never really see it in the show... or in a Movie, for that matter. The characterization of the show's main characters (Scooby Crew et al., Cordelia, Giles) were all good.
Basically, if I take a step back from the comic and put down the magnifying glass that I usually pull up to go over an episode on the second viewing, than I really, really, enjoy the Dust Waltz. Your Mileage May Vary, so I'd suggest picking up a copy. :)