I thought the book was pretty solid.
We were given a very detailed description of the new Deep Space Nine, a rather interesting story regarding Keev/Kira, Odo accepting a chance to contact a new shapeshifter-esque species, the assassination of President Bacco, the Tzenkethi possibly behind the assassination, and the return of Taran'atar. For this being the first of a five-part miniseries, I was VERY satisfied.
We also go to see how nearly every character is struggling with issues that will ultimately be resolved - for better or for worse - at the end of this miniseries.
It was a good set-up for the next four books. DRGIII is one of the best 'Trek writers (in my opinion).