We currently make use of Team Track, Quality Center and Rally. Team Track has been used for years in our company and we have made strong use of its workflows. Where I have not seen an implemtation of work flows in Quality Center or Rally. We are currently working to integrate Quality Center with Rally for defect tracking and work packaging. As far as a defect tracking tool that will do some of the work for you Team track has a strong pull. The work flows alow for general setup of notifications and defaulting of responsible users as a defect moves through its life cycle. From what I have seen of our current implimentation of Quality Center all of the movements through the life cycle and assigning of users is manual. We will see what comes from the changes that we are working to put into place in the first half of this year with triggers on the database and other customizations. For the tie between test cases, test case execution, requirement and the defects Quality center has the ability to bring all of this together. Where in Team track I have not seen this ability.