'Rivals' introduces a new character, a Listener: Martus, whose race is identified as El-Aurian, presumably the same as Guinan from TNG. Instead of advising starship captains in the face of the enemy, however, he uses his listening powers for immoral gains–setting himself up for economic combat with Quark when Martus takes an alien Nintendo DS from the dead body of a prisoner.
I actually liked the character, but he felt like a drop-in from the beginning, and I was waiting for him to drop all the way in throughout the episode. His rivalry with Quark is fun, but as the game goes on it starts to become obvious the entire thing is being carried on the shoulders of Shimerman. Even in the beginning, it's Quark who has to go "Gee, what is that? Can I try?" to Martus (I was reminded of a play I once saw with a really sympathetic actor trying to adlib for his drunken compatriot until he remembered his cue.) After a while he was just a cliché gone wrong here to show us an alien-gadget-of-the-week.
The idea of a device that altered the laws of probability, by the way, made me go totally Douglas Adams; I kept expecting Dax to morph into Trillian and see Bashir go "Hey, I'm a cool guy, you know?" So geek points for that.
The inner storyline - the developing relationship between Miles and Bashir - actually struck far more of a chord than the huge operatic, but ultimately flat, rivalry between Martus and Quark. You feel for Bashir - whether he does his best or his worst he's doomed to make his friend look bad. I loved that he isn't going to sacrifice himself, either; the moment when he finds the drugs Quark's trying to sedate him with is a very Bashir moment. On the other hand it was Miles who gets the first inkling something's up, stops the ultimate match, and reports to the Captain; this shows age and experience does count for something, even with the laws of chance up in the air. I can see these two developing into a fine team in the future.
Bits and Pieces
The early shot of Dax and Bashir eating, right after Bashir's first game against Miles. There was just something so deeply characteristic of Bashir politely taking everyone's condiments.
Keiko's sendoff of Miles, with the headband and perfume. Wonderful.
Dax and Sisko, destroying all the machines instantly when it becomes clear they're a totally unknown danger to the ship. A fine moment of quickly-communicating teamwork.
One weird logical gap - is it that easy to replicate functioning power-sourced products in the future without Odo's knowledge?
Martus: You were snoring.
Cos: Please accept my apologies. I didn't mean to disturb you, but as you can see, my health is not so good.
Martus: Yes, well, I'm sorry I had to wake you.
Cos: I wasn't always like this.
Martus: Of course not.
Cos: I had youth, vigour, fame, wealth beyond measure. All gone.
Martus: I'm not listening.
Rom: I always had smaller lobes than the rest of the boys. They used to tease me about it. Quark was the worst. He told everyone I was adopted.
Bashir: It goes right into his hand. Every single time.
O'Brien: I must have done it a dozen times by now. And I haven't missed once yet.
Bashir: Nobody can be that lucky. It's impossible.
Dax: Not impossible, just extremely improbable.
A bit meh. I liked it when I watched it, so say but this: This story done, I went and watched the next. One point for the geeks, and one for Miles and Bashir. So two out of four angelic Bajoran orphans.