The SysML requirements system is highly usable standalone on real-world projects and - unlike other requirements management systems - integrates fully with the most powerful model-based graphical engineering tools!
Dr Darren says:
Integrations with some other requirements management systems are available for the MagicDraw SysML Plugin and Magic Cyber-Systems Engineer ® (Cameo Systems Modeler®), but in many cases synchronising with another external requirements management system will only diminish your return on your investment in graphical, model-based systems engineering. You may be better off investing in training in SysML Requirements for relevant team members so they can all just use Cameo Requirements via the Teamwork Cloud.