Good Romance, Bad Followup.
Airplane's relationship-building is always a favorite of mine. He has a very good one with his Tangled fics and it also shows in this Zuko/Jin pairing. I loved Jin's characterization and snark as the two built up familiarity with each other.
Having said that, once they actually get together and the plot suddenly veers into more action/adventure, Jin suddenly becomes closer to Sue-territory than I am comfortable with. Zuko training her with blades in a kneejerk overprotective reaction is rather cute. Her suddenly being able to take on military firebenders and callously taking lives is... less so. That's just one of the things that bugs me about this story.
However I would still recommend this fic, although it's mostly for the first half romance/waffyness. Reading after that point is up to you; YMMV.