As Jeff and aaron have said, data integrity can be the main issue with document storage, regardless of what people may say about performance.

With Filetable storage, I think you can prevent anything other than SQL Server from deleting or adding documents. Filetable objects are also included in SQL backup and restore, which means data integrity is maintained through these operations. This effectively unifies the management of the documents and meta data.

If you design a system with the documents and meta data being stored in separately managed containers, you should not expect the two containers to remain consistent.