Tough question because it's so subjective... but basically I thought their feelings were by far the most believable...
Also the story develops so well... at first it's just her attraction to him and I love how she has to work so hard to win him over... then once they were together you could just ...
I know I'd have loved to have seen Worf get revenge on Dukat... but on the bright side Dukat does end up stuck with the Pah-Wraiths in some sort of eternal damnation-style punishment.
I'm not sure what they're saying either, but I found this translation posted by someone whose handle is OuroborosCobra and says it's from the script of the episode.
DAX: MoVas ah-kee rustak. (Today was a good day to die.)
WORF: Kosh tomah... ehpaq Lukara kaVeir. (The day is not yet over, Lukara.)...
You're welcome, it was fun making them.