MS SharePoint is a great tool to use for smaller efforts - such as Task Orders. However, it is not capable of handling high volume efforts. Additionally, SharePoint does not allow for comments to be made without locking down the document, which is simply not ideal for review teams when multiple users are reviewing a single document. MS SharePoint additionally has a history of security issues from the back-end, and any user / subcontractor could find their way into classified information that should be better protected. As for Office 365, it is more beneficial from a senior management position. It allows for graphical representations and manipulations of certain data so that senior management and project / program managers may see the project / proposal in snapshot form. However, it may be a bit too involved from a proposal standpoint. In the end, I believe that Privia is definitely a better, more organized option when coordinating between various users and companies that not only protects the proposal, but also the company.