During our event some days ago in Busto Arsizio, I've received an interesting question from a customer: "Can I plan to use Sharepoint as a document management system and move all my File Shares into the MOSS platform?".
Answering to this question is not so simple because I think that many aspects must be taken into consideration.
The first aspect that I always try to put in evidence when I talk about this topic is that File Shares are a technology that has the scope of storing data, while SharePoint is all about connecting people to information. Sharepoint is actually a great document management system with lots of "plus" such as Document Versioning, Office integration, Recycle Bin, Web Access, Metadata and (my top feature) Workflows.
All these feature together makes Sharepoint a complete enterprise platform that can't be reduced to be only a document management platform. SharePoint must not be viewed as a replacement for file shares, but instead it must be viewed as a platform that makes data accessible and useful no matter where it’s stored.
Why this?
Because in a Sharepoint environment you can directly store documents inside a document library, but you can also use the Business Data Catalog and use Sharepoint as an interface to access your File Shares.
You've to remember that Sharepoint stores document internally on SQL Server by using BLOB fields (limits of 2Gb of data for a single document). SharePoint lists work well with files under 50MB and can be used up to 2GB, with configuration.
Sharepoint is not a competitor or a replacement for File Servers, but instead it can give you a new way of work with your files, based on a complete collabouration and on productivity improvements.
However, there's an interesting post here where you can obtain more informations on this topic.