Yes you can do gap analysis with RRC, for example, which features are not associated with use cases? When using the other parts of Rational Collaborative Lifecycle Management, you can ask similar questions:

* Which requirements have associated development tasks and test cases?
* Which have dev tasks that are done?
* Which have test cases that have failed?

Compared to RequisitePro there are some gaps in functionality. I would say these may be the most significant:
* RRC V3 has a simpler security model: no access controls on a requirement type, for example.
* Different integration with MS Word: RRC V3 has import from Word but not on-going editing of the requirements in Word after putting them into the RM repository
* Integrations with other products are different

Compared to ReqPro there are many new capabilities; I won't list them here, but you can read a summary in this product data sheet . The big point here is that RRC gives you the opportunity to consider new "degrees of freedom" in how your teams do their requirements definition and management.

The best way to get started is to download the trial version, create a sample Money That Matters project, and follow the task guides and videos in the information center.

Beyond that, IBM can help you with these extra services:
* Introduction to RRC education course. 2 or 3 days (I don't remember); an instructor can come to your premises.
* RRC Quickstart. Helps with planning, installation/configuration, usage model considerations, and some end-user training.

I should also mention that we have released the first beta milestone for the first RRC V3.0.1 fixpack. This beta contains an early version of the code that migrates data in ReqPro baselines to RRC.

You can read more here:
https://jazz.net/downloads/rational-requirements-composer/milestones/3.0.1.1M1

And you can follow the progress in the
3.0.1.1 plan