Read this a couple of weeks back.
I really enjoyed the main plot, DRGIII really conveyed the shock of the assassination very well. The links to the previous books were done well too.
The flaw was in the Kira plotline, I can't really see any reason for it so the only conclusion I can draw is that it's going somewhere, which means future books. I'm also suspecting we may get the Ascendants story told by stealth, which I'd also be happy with.
Still, it was a good opener, though I'm uneasy over Sisko's daughter's likely fate from what was suggested here.