SABR Matt and I are certain to disagree on this one.
Memory Alpha summarizes the episode here.
I appreciate the point the writers are trying to make here -- i.e., that unambiguously evil people do exist. I have in fact advanced a similar argument before (while discussing another canon). I can even accept that deep down, beneath all the self-delusion and self-justifications, Dukat does want to destroy the Bajorans for the sin of insufficiently flattering his enormous ego. The thing is, I understood that before the writers started to lay it on thick with an industrial-sized trowel. Yes, Dukat has his apologists, but I've never been one of them.
When you get right down to it, the reason I dislike Dukat's metamorphosis into Eeeeeeeeeeeevil Dukat is that it is a metamorphosis. I'm able to accept a character like Cartagia (from Babylon 5) because he was portrayed as batshit insane from moment one. With Dukat, however, we were originally presented with an alternative style of characterization that actually worked extremely well -- and why fix something that ain't broken? Because some idiots out there don't understand that Dukat has always been evil despite his multilayered personality? I don't know. I feel like my intelligence has been insulted somehow.
Plus, my inner Bajoran nationalist chafes at the fact that the writers make Dukat Sisko's nemesis. Yes, yes, yes -- the Sisko is the Emissary, and the Emissary is "of Bajor," but in the end, Sisko was not personally victimized by Dukat during the Occupation. By all rights, it should be Kira who stands as Dukat's opponent.
The writers didn't need to make Dukat's evil so blatantly obvious. The choice betrays a lack of trust in the audience that I find rather grating.
Generally speaking, the performances are pretty good, though there are a few moments that push things over-the-top.
Is there such a thing as true evil? Absolutely! But this episode feels a bit two-by-fourish on this front.