Datasite: Datasite offers real-time collaboration, and Q&A modules that are highly useful in due diligence processes. Investment bankers can answer queries very efficiently in real time with team members and other stakeholders.
Intralinks: Intralinks is more about collaborative complex deals, where it has an elaborate Q&A section with permission controls, and collaborative workflows. It comes with "auto-indexing" where files are organized effectively, and it saves much time.