It's hard to choose. I've done a main arc marathon for both and they're both pretty epic, but if I had to choose between An epic voyage home vs. The emissary and the star trek battlefront, I'll go with DS9.
Would you rather have an evil twin replace you or live in the mirror universe for a day?
The mirror universe. I'd love to see how I would turn out if circumstances in my life had been different.
Would you rather award sentience to Data or the EMH?