I liked the use of holographic technology in "Business as Usual" to sell illegal (or at least questionable) things in an open forum. It just makes sense that the technology would be used in that way. Plus, it's safer. Even if you're not selling dangerous things, it's nice to know the customers can't steal your stuff from your shop (holosuite).
I felt that the Starfleet characters (like Dax) were too quick to judge Quark just because he was an arms dealer. She does realize Starfleet makes and buys (and maybe sells) weapons too, right?
One more random observation: I guess it's just luck of the draw (or whim of the writers) as to which family members get developed more on Star Trek. Gaila's been mentioned a couple of times, a gift from him was a significant plot device in "Little Green Men", now he's featured in an episode, and he'll probably be revisited again. Yet Jadzia's mother and sister were only mentioned once and never seen, Sisko's brothers only mentioned once and never seen, Geordi's sister only mentioned once and never seen. This is just a small complaint, but I wish we had seen little glimpses of family members visiting from time to time. Or at least mention the visit in passing, like when they twice mentioned that O'Brien's father had visited. It just adds a sense of reality to the show.