In UX requirement practice and research, it has been widely acknowledged that usability and user experience should be addressed in every aspect of the product development process. However, challenges exist on how to consistently and explicitly conduct the usability evaluation and improve user experience. In this paper, I will present how we have tried to improve user experience with interactive information systems by employing a consistent task design and a set of evaluation metrics. An integrated interactive information retrieval system is introduced as an example. Task design and user experience metrics used in a user-centered experiment evaluating this system are described. The task design scheme and user experience metrics have been applied in other user experiments to test the effectiveness of some other information systems and they have been proved effective. Successful experience and lessons learned are discussed. Some further thoughts and suggestions on future work are also presented.