I'm not too bothered by the spoilers. I make a few myself, though I try to keep things vague enough by not explicitly stating future plot points. I know that there was another first-timer here a few months ago that was spoiled on Cardassia joining the Dominion, but I think they were scared off to Shatnertage's thread because it's mostly free from spoilers.
Explorers (****)
DS9 finally grows the beard.
There's an old Irish myth about a monk called
Saint Brendan (the saint title obviously came later) that embarked across the ocean in the 6th century in a crappy boat with a small crew, and the legend claims that he managed to make it all the way to North America before returning home. There's no way of knowing if the story is true, but if he did then he would have been one of the first Europeans to make the voyage. Back in the 70s a crazy man called Tim Severin decided to test the legend and built a replica of a traditional Irish boat from that era using period tools, then he set sail across the ocean. He was never heard from again. Nah, I'm kidding, he actually managed to
make it to Newfoundland thus proving that the story was plausible. When I was a kid I got to see the actual boat that Severin sailed across the ocean in while on a school trip to a historical park, and it was kind of exciting.
To the people that say that DS9 wasn't "true" Star Trek because it wasn't about exploring, I think this episode is a good example of why you're wrong. TNG, though I love it, was about a bunch of people in a 5-star resort that could request any item they desire from a replicator or live any fantasy in a holodeck. But in this episode Sisko builds a crappy little ship by hand and sets sail into the void because he thinks it will be fun. This episode better encapsulates the spirit of exploration than almost any other episode of Star Trek, and it temporarily turns a 26 year-old man into a 10 year-old boy that looked at a crappy little boat and thought it was one of the coolest things in the world.
Is the plot plausible? Not really. How does jumping to warp for 10 seconds bring the ship from Bajor to Cardassia? Did Sisko find another wormhole in the Denorios belt and not notice? What powers the gravity net? How did the Bajorans get their wooden spaceship into orbit? Ah well, at least we get a pleasant (there's that word again) father/son story out of the whole affair. It's about time there was another episode about Jake, he has been MIA for the last seven episodes. Having him become a writer is as good a direction to take him as any, and this episode also clears the way for the introduction of Kassidy Yates.
Meanwhile, O'Brien and Bashir get drunk. There was some sort of story here, but that doesn't matter, all that matters is that O'Brien and Bashir get drunk and O'Brien admits his not-hate for Bashir. It's very touching.
It manages to be almost genuine as a political (and personal) olive branch, a friendly gesture between neighbours, while also allowing Cardassia politically and Dukat personally to maintain a slightly smug "upper hand" despite the potential embarrassment. Well played, Dukat, and well played, writers. 
