Odo struggles to witness Kira starting a relationship.
This is a reasonably good episode with some decent character development for Odo.
It depends on how much you care for the Odo/Kira arc for how much interest you can take in this story. Rene Auberjonois does a great job of portraying a character tortured by his feelings for someone.
Another good aspect is how Quark's enemy/best mate relationship with Odo plays into the problem and it further develops the bond between the two characters.
Where it slightly falls down for me (as usual in the writing Star Trek episodes) is the romance between Kira and Shakaar. He was portrayed as quite an interesting character in the previous appearance in the episode 'Shakaar', but unfortunately this time he is reduced being a simple love interest. Duncan Regehr is a great actor but he cannot save the bland characterisation and lack of effort made by the writers to make it a plausible coupling.
Personally I think it would have been better to have sent the three characters on a cool mission somewhere and let the love between Shakaar and Kira develop from that, with Odo observing. Crossfire depicts a typical Trek romance where characters are in love because they just are.
Overall though there are more positives than negatives, particularly the performances and continuity of on going character arcs.
For me it's a 6.5/10 but I round upwards.