I thought DS9 was the best series of them all, but yeah there are a few that make me say "oh no not this one again." As for Quark, he was (as someone once said) the only person that never went against his "ethics". If the "Rules" said dont do it, he wouldnt. Alot of other "Starfleet people" in this one, and all the other series, found a way to get around some Starfleet rules but never got in trouble 1) because they where one of the main character and that just cant happen and 2) it would be said that they did it for "the good of the people." In my opinion DS9 was more realistic than the others, if that is possible. That might be why "true trekkers" dont like DS9, because it is something differant from the norm.