Jin-Gitaxias, Progress Tyrant rewards careful spell timing. The first artifact, instant, or sorcery spell you cast each turn is copied, while the first qualifying spell cast by an opponent each turn is countered. That creates both value and a barrier opponents must account for before resolving their important plays.
Your copy can be a second artifact permanent, another draw spell, or a second instance of removal with new targets. Because the ability works once each turn, instant-speed spells let you receive value on opponents' turns too. A useful spell during your turn and another during an opponent's turn can produce separate copies without waiting for a full round to finish.
The defensive ability is once each turn across all opponents, not once per opponent. One player can cast a disposable qualifying spell to use it up, allowing another spell through later that turn. Creature and enchantment spells also avoid that trigger unless they are artifacts. Jin-Gitaxias therefore complicates opposing sequences without automatically preventing all interaction.
The first eligible spell uses the trigger even if you would have preferred to save it for something larger. Lead with the spell you most want copied, and remember that copies are not themselves cast. Seven mana makes the Praetor a major investment, so the best home is a deck already rich in artifacts, instants, and sorceries, with enough instant-speed activity to benefit from more than just its own turn.
