I think by now (2389), the Cardassion Union is in much better shape than it was after the war. Fourteen years have passed since the Battle of Cardassia, and while many key cities on the planet were devastated, a great deal of reconstruction has likely been in progress during that time. With possible humanitarian aid from the Federation and several other nations in the form of medicines, foodstuffs, industrial replicators, etc., the Cardassian Union's infrastructure may be well on the road to recovery by now, although there is probably still much work to be done before it can return to pre-war status.
Military-wise, though, I think the Cardassians probably had to enter into their own version of the Khitomer Accords (the Chin'toka Accords, perhaps?) during reconstruction.
IIRC, the Cardassian forces fared about as well as the forces of the Federation-Klingon-Romulan coalition as they switched sides against the Dominion during the final battle.