Just to expand on the topic, there are two types of undertaking here...
1) Use a project that is actually located on a server.
TMG's networking tools are weak at best and users have experienced various problems connecting to servers.
The only genealogy database manager that is designed to work with the database on a server (and thus allowing sharing) is Ancestral Quest. If any others have been added to this list of one, please update this discussion.
2) Syncing with a server (Dropbox, OneDrive, iCloud, Google Drive, Amazon, others) using a local client.
Based on my collective experience repairing (or attempting to repair) user projects who have undertaken to sync their live project, I'd say that this is a surefire way to destroy a project.
You don't want to sync any file that has to do with working on a live TMG project.
You can sync anything not connected to a live project... for example, TMG backup files that have been copied to a folder being synced.
The fundamental problem is that a TMG project is a _set_ of 48 files that all must be in tune with one another. Get any one file out of sync with the other files in the project and the project is corrupted.