A much better "prequel" to the TV series than the "Buffy: Origins" two-shot, this actually manages to capture Joss Whedon's unique combination of high character drama and witty verbal comedy in a much more convincing way than the amalgamation of the film script and the TV show that Origins attempted. Pike is, here, a much more sympathetic character, and it makes total sense how this could possibly lead into the TV series. So too is the back-story of how Giles ended up becoming Buffy's watcher far more plausible than any other theories ever really given -- and it provides a fantastic bridging of the gap between Buffy's L.A. days and her move to Sunnydale.
By far the most controversial thing I'm sure will be the addition of Dawn to the story, but it makes total, complete sense if you think about it. For better or worse, "Buffy vs. Dracula" introduced a brand-new element into the show, and it changed the entire history irrevocably. It would be disingenuous of the writers -- ANY writers -- to revise what is already revisionist history. Dawn is an integral part of the Buffy mythos now. Every character can remember her. While we as viewers might go back and watch, say, Season 3 and think, "Man, Faith would totally have kidnapped Dawn" or something, that's looking at it the wrong way. The RIGHT way is to view it as, "Seasons 1-4 happened, then something changed the plotting beginning in Season 5 (or, more accurately, in 'Restless,' if you REALLY want to get technical about it), and now, any *subsequent* productions really must include the fallout from that plotting change."
That aside, what's really fascinating is to see, even briefly, the disintegration of Joyce and Hank Summers' marriage. It's interesting to think not only that Buffy was the catalyst for their breakup, but that she dealt with the trouble by doing exactly what she did at the end of Season 1 AND Season 2: ran away. It's entirely in keeping with her character. And it's brilliant plotting to bridge that gap.