Works well ONCE you know what you are doing. We replaced most of file shares, and intranet, project drives and manage file shares internally and externally with it. Its integrated with Office 365 and MS Teams. In fact these kinda sit on top of SharePoint. So to use it you need to have a good knowledge of Office 365.
From the wiki. "SharePoint allows for storage, retrieval, searching, archiving, tracking, management, and reporting on electronic documents and records. Many of the functions in this product are designed around various legal, information management, and process requirements in organizations"
Problem I have we we migrated with very poor training of our user base. Because Office 365 cloud and collaborative working require a sizeable step up in skill set over local copies of Office and Network File Share. Some people will never get it.
The other issue is, you need a naming convention for SharePoint sites, and how you will administer it, we use Azure Active Directory. Some users manages refuse to comply or adhere to the rules, so administer it themselves without knowing how it works, so some sites become a confused mess.
The interface is clunky though. Microsoft loves to make simple things complicated.