Recently Sebastian Wohlrapp and I published a whitepaper on open source document management systems. If you are looking for a solution in this area, you also might want to add Infrae's Document Library to the list of products to consider. I have not yet tried Document Library but have used their Silva WCM product which does a very good job of versioning and workflow. One thing that caught my eye is their support of the Open Archives Initiative's Protocol for Metadata Harvesting (OAI-PMH) which might become an important standard for companies implementing a distributed/federated content management strategy. Here is a good description from the OAI-PMH Tutorial
The essence of the open archives approach is to enable access to Web-accessible material through interoperable repositories for metadata sharing, publishing and archiving. It arose out of the e-print community, where a growing need for a low-barrier interoperability solution to access across fairly heterogeneous repositories lead to the establishment of the Open Archives Initiative (OAI). The OAI develops and promotes a low-barrier interoperability framework and associated standards, originally to enhance access to e-print archives, but now taking into account access to other digital materials. As it says in the OAI mission statement "The Open Archives Initiative develops and promotes interoperability standards that aim to facilitate the efficient dissemination of content."
If OAI-PMH sounds interesting, you may also want to consider looking at DSpace which is gaining adoption in academic research environments such as MIT.
In addition to OAI-PMH, Document Library does automatic document conversion (using OpenOffice - just like Alfresco), workflow, versioning and other things you would expect from a DMS. In terms of architecture, Document Library is built on the Zope 3 platform and uses the Silva Tramline for rapid upload and download of files.