IBM Rational DOORS is a robust and performant tool.
It includes all what is needed to manage requirements through the lifecycle in the most professional maneer:
1. First it's robust: If you put something in DOORS, the date integrity of what you have put is garanteed. It's not always the case with other tools.
2. It's fast. Even with hundreds of people connected, it still has very good reponsive time.
3. It's built for Requirement Management. You requirements ares stored in objects with properties to categorized them, and the traceability is perfectly handled.
4. It gives some basic capabilities for configuration management and testing: If you don't have too complex testing and configuration management needs, there are some features that can help you handle that (baseline, baseline sets, ..)
5. It offers different perspectives on the requirements for different profiles through the use of views.
6. And, for me, the aspect that makes DOORS so good and attractive, it provides you with the capability of customizing it to your need through DXL which is a language built on a requirement management Model. I am not a specialist of it yet, but I must say that I am impressed by what you can do with it.
There are two things, in my opinion, that should be improved in DOORS.
A. Its usability: DOORS is not an intuitive tool. You have to get used to it. Once you have been using it for a while, than you cannot spend one day without using it, but if it was more intuitive, that would help people like me convincing other people who are not especially fans of requirement management to use it.
B. It external API. Calling a tool via DOORS through OLE is very easy and woks very well. But apart passing a string to DOORS, or delving in complex C code, you cannot handle DOORS from outside.
Conclusion; In my modest opinion, DOORS is the state of the art Requirement Management tool. But my message to the development team...please make it even better by improving its usability and the way it can be called from other tool.
Pros: Manage project complexity, Reduces rework, Aligns project deliverables to requirements and business goals, Facilitates requirements reuse, Enhance collaboration across engineering discipline with all stakeholders