The DMN Standard is already supported by different vendors and it means that real (not theoretical) interchangeability of the same DMN-based business decision models became a reality – see examples at this article. If you attend the RuleML+RR+DecisionCAMP conference in London in July, you will see a live demonstration of how DMN XML decision models can be created using Trisotech or Signavio DMN modelers and then executed by Drools or OpenRules rule engines.