This episode directly challenges two - TWO - Trek shibboleths -- and for that, it deserves a place in the top tiers.
Memory Alpha has a summary here.
There are two main things that SABR Matt and I really like about this episode. First of all, the way the writers handle Weyoun 6's defection is delightfully unexpected. You would think, given Trek's generally secular outlook, that a "defective" Vorta would entirely renounce his gods. But that is not what happens here. What happens here is far more nuanced. Weyoun 6 is not an atheist; he is, instead, a man of deep faith who seeks a reformation. And by the way, while we're at it, the text of the episode absolutely refuses to mock the Vorta for his trust in Odo. On the contrary, Weyoun 6's martyrdom for Odo's sake is treated with utmost seriousness. The writers clearly highlight this as a turning point for Odo - as the moment in which he decides to return to the Great Link to heal his people. They also allow a main character - i.e., Kira - to express sympathy for Weyoun 6's beliefs, thereby granting said beliefs a profound sense of legitimacy. Folks, this yet another reason why we've repeatedly argued that DS9 handles religion better than any other Trek.
Secondly, the B-plot is unabashedly pro-Ferengi and pro-capitalist -- another shocker. Usually, the Ferengi are portrayed as grasping, greedy little trolls -- a default we despise because it's obvious propaganda. Here, on the other hand, we're permitted to see Nog's Ferengi upbringing as an asset. If Nog had not greased the wheels in his unique fashion, O'Brien would've been stuck in a socialistic wait-list hell for weeks. Oh, and for your information: The Great Material Continuum is not simply a Ferengi fairy tale. It actually exists. We real-world capitalists just refer to it as the natural order. Market economies arise not because somebody consciously directs their development. They blossom into being because, as Nog notes, each person instinctively tries to use his surplus to get something he lacks. And money? We use money because barter is clumsy and convoluted -- as this episode hilariously reveals.
I'm crediting the writers here for avoiding the obvious course.
The performances are not what I chiefly remember about this episode, but they still warrant a solid B.
See the discussion above.