If you're using a Sharepoint server to manage documents across an organization, MS Office has Check-In & Check-Out capabilities integrated directly into MS Word

If you're using a Sharepoint server to manage documents across an organization, MS Office has Check-In & Check-Out capabilities integrated directly into MS Word. You're logged into the server through MS Word and you can manage visibility of your check-ins (ie whether it's a minor edit only visible to your direct collaborators, or a major edit visible to all people with access rights to the document). If something like that is key to an organization's workflow, competitors will probably be locked out even if they do add support, because it's like using "non-genuine parts". It will probably work 99% of the time, but it's probably less reliable than the general part, and hard to get support for the cases where it does cause problems. Reliability & consistency is often more important than cheaper upfront cost. (I say this as a long time NeoOffice fan & paid supporter of the project.)