I'm personally not crazy about cameo episodes - there were a few of these in season 1, and they were generally pretty stupid. It seems like a high profile guest offers the writers an opportunity to coast - who needs a good story when this hotshot guest is dominating the camera?
This one is much better, and that's because the writers actually went to the effort of providing an interesting, exciting plot. After the first viewing, the shock of Tom Riker's reappearance wears off - particularly once you realize he won't ever show up again. On the flipside, the Dukat-Sisko scenes provide plenty of excellent chemistry, and the Obsidian Order arc moves toward its surprising resolution later in the 3rd season. There's one scene - where Dukat discusses not being able to take his son to an amusement park - that's particularly well written.
Not a classic, but a fun and ultimately pivotal episode.